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Showing papers in "Journal of the Optical Society of America in 1961"


Journal ArticleDOI
TL;DR: In this paper, the roughness of a plane surface is related to its specular reflectance at normal incidence, and expressions for the case when the root mean square surface roughness is small compared to the wavelength of light are presented.
Abstract: Expressions relating the roughness of a plane surface to its specular reflectance at normal incidence are presented and are verified experimentally. The expressions are valid for the case when the root mean square surface roughness is small compared to the wavelength of light. If light of a sufficiently long wavelength is used, the decrease in measured specular reflectance due to surface roughness is a function only of the root mean square height of the surface irregularities. Long-wavelength specular reflectance measurements thus provide a simple and sensitive method for accurate measurement of surface finish. This method is particularly useful for surface finishes too fine to be measured accurately by conventional tracing instruments. Surface roughness must also be considered in precise optical measurements. For example, a non-negligible systematic error in specular reflectance measurements will be made even if the root mean square surface roughness is less than 0.01 wavelength. The roughness of even optically polished surfaces may thus be important for measurements in the visible and ultraviolet regions of the spectrum.

1,049 citations


Journal ArticleDOI
TL;DR: In this article, the propagation of cylindrical dielectric waveguide modes near cutoff and far from cutoff is considered and the relative amounts of Ez and Hz, and the transverse components of the field are determined for both sets of hybrid modes.
Abstract: The propagation of cylindrical dielectric waveguide modes near cutoff and far from cutoff are considered. The relative amounts of Ez and Hz, and the transverse components of the field are determined for both sets of hybrid modes. With the radial dependence of the z components of the field in the central dielectric given by Jn(ur/a), the transverse components far from cutoff are given by Jn±1(ur/a), where u is a parameter found from the boundary conditions and which fixes the scale of the Bessel function relative to the boundary r = a. The two values n + 1 and n − 1 correspond to the two sets of modes. The designations of the hybrid modes are discussed. Field plots for the lower order modes are given.

643 citations


Journal ArticleDOI
TL;DR: Classic relationships as the Ferry-Porter, Talbot-Plateau, and Weber-Fechner laws are derivable from the present results, as descriptions of the behavior of certain parts of the amplitude sensitivity curves as functions of adaptation level.
Abstract: With sinusoidal modulation of the radiance of the stimulus as a function of time, amplitude thresholds are measured instead of the repetition-rate thresholds usually obtained in flicker-fusion experiments. Controlling the modulation amplitude independently of the time-average radiance provides an additional degree of freedom, so that the observer’s adaptation level can be held constant while his amplitude sensitivity is measured as a function of the modulation frequency. With an “edgeless” flickering field, these amplitude sensitivity curves show a broad peak of maximum visual response, in the region from 10 to 20 cps at high photopic levels. Such classic relationships as the Ferry-Porter, Talbot-Plateau, and Weber-Fechner laws are derivable from the present results, as descriptions of the behavior of certain parts of the amplitude sensitivity curves as functions of adaptation level.

543 citations


Journal ArticleDOI
TL;DR: In this article, a new method for transforming observed radiances into the radial distribution of the emission of a plasma is described, which is applicable to optically thin plasmas with cylindrical or spherical symmetry.
Abstract: A new method for transforming observed radiances into the radial distribution of the emission of a plasma is described It is applicable to optically thin plasmas with cylindrical or spherical symmetry, which are often encountered in plasma physics and astrophysics The observations are introduced as a sequence of n readings on the experimental curve, which are then transformed to a set of values for the emission coefficient The transformation coefficients are tabulated for n=10, n=20, and, in part, for n=40 The method is more accurate than previously published ones and is well suited for rapid calculation by electronic computers The sources of errors are discussed and a numerical method for smoothing the readings is suggested

332 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used the central field approximation used by Bates and Damgaard to calculate the lifetime of the lower excited states of atoms of the alkali metals, and the branching ratios for downward transitions and total lifetime of states were tabulated.
Abstract: Lifetimes for radiative transitions between the lower excited states of atoms of the alkali metals have been calculated by using the central field approximation used by Bates and Damgaard. Branching ratios for downward transitions and total lifetimes of states are tabulated.

233 citations


Journal ArticleDOI
Frank J. Low1
TL;DR: In this paper, a bolometer using gallium-doped single crystal germanium as the temperature sensitive resistive element was constructed and operated at 2°K with a noise equivalent power of 5×10−13 w and a time constant of 400 μsec.
Abstract: A bolometer, using gallium-doped single crystal germanium as the temperature-sensitive resistive element, has been constructed and operated at 2°K with a noise equivalent power of 5×10−13 w and a time constant of 400 μsec. Sensitivities approaching the limits set by thermodynamics have been achieved, and it is shown that the background radiation limited or BLIP condition can be satisfied at 4.2°K. An approximate theory is developed which describes the performance of the device and aids in the design of bolometers with specific properties. The calculated noise equivalent power at 0.5°K, for a time constant of 10−3 sec, is 10−15 w. The detector is suitable for use in both infrared and microwave applications.

228 citations


Journal ArticleDOI
TL;DR: In this paper, the optical constants and reflectance and transmittance of aluminum films with very fast evaporation were determined by Drude's polarimetric method from opaque films and by reflectance, transmittances and true thickness measurements of semitransparent films.
Abstract: The paper presents new measurements of the optical constants and of the reflectance and transmittance of evaporated aluminum films produced from the purest grade of aluminum with extremely fast evaporation at about 10−5 mm Hg. The optical constants were determined by Drude’s polarimetric method from opaque films and by reflectance, transmittance, and true thickness measurements of semitransparent films. The following results were obtained. λ (mμ)220260300340380436492546578650n0.140.190.250.310.370.470.640.820.931.30k2.352.853.333.804.254.845.505.996.337.11R%91.892.092.192.392.692.692.291.691.590.7For extremely fast evaporated films the optical constants were found to remain unchanged down to film thicknesses of less than 100 A. Data are given on the reflectance and transmittance of semitransparent aluminum films on glass and fused quartz as a function of wavelength from 220 mμ to 650 mμ.

226 citations


Journal ArticleDOI
TL;DR: In this paper, the electro-optical coefficient of zincblende is measured by using the Senarmont compensator method for various wavelengths between 404 and 644 mμ and the application of the crystal to light modulator of wide optical aperture is discussed.
Abstract: The electro-optical coefficient of zincblende is measured by using the Senarmont compensator method for various wavelengths between 404 and 644 mμ and the application of the crystal to light modulator of wide optical aperture is discussed. The electro-optical coefficient is found to be 5.9×10−8 cm/statvolt at room temperature for wavelength of 546 mμ. The voltage for obtaining half-wave retardation is about 10 kv.

193 citations


Journal ArticleDOI
TL;DR: In this paper, a phase Fresnel lens is inserted in the pupil of the optical system to deform the wave surface passing through an optical system by the amount ϕ(u,v).
Abstract: In order to deform the wave surface passing through an optical system by the amount ϕ(u,v), it is suggested that a phase Fresnel lens be inserted in the pupil of the optical system. Assuming 0⩽ϕ(u,v)

189 citations


Journal ArticleDOI
TL;DR: An integrating sphere for determining spectral reflectance and transmittance as a function of angle of incidence and wavelength in the 0.33- to 2.5-μ region is described in this paper.
Abstract: An integrating sphere for determining spectral reflectance and transmittance as a function of angle of incidence and wavelength in the 0.33- to 2.5-μ region is described. Geometrical arrangement of sample, entrance port, and detector as well as directional characteristics of detector and sphere wall coating permit absolute or relative measurements to be made for a sample with an arbitrary reflection-distribution function.

189 citations


Journal ArticleDOI
TL;DR: In this paper, two general receiver types are considered and termed, following rf terminology, low-level and superheterodyne receivers, which offer the possibility of simple observations of the special shape of the laser output, although good resolution will require long observation times.
Abstract: Photoelectric mixing is at present an effect which can be displayed with great difficulty. When combined with optical masers (or lasers), it may provide the basis of relatively simple optical measurements using radio-frequency-like receivers. In these receivers the detector or mixer is a photocell or other photoelectric device. Two general receiver types are considered and termed, following rf terminology, low-level and superheterodyne receivers. The low-level receiver offers the possibility of simple observations of the special shape of the laser output. The superheterodyne receiver offers the possibility of measurement of the shapes of ordinary spectral lines although good resolution will require long observation times. As an instrument for comparing two laser outputs the superheterodyne optical receiver is capable of such extraordinary sensitivity that two lasers may be compared out to physical separations of 106 km.

Journal ArticleDOI
TL;DR: In this paper, the chromatic response processes of the opponent-colors theory were analyzed in terms of the Chromatic response process of the inducing field, and it was shown that induced chromatic responses are opponent to but proportional in magnitude to the mean chromatic activities of inducing field.
Abstract: The concept of physiologically based, opponent chromatic induction is fundamental to the opponent-colors theory. A continued quantitative development of this theory to account for color perceptions, equations, and discriminations under various conditions of adaptation and illumination has emphasized the need for systematic quantification of induced color effects. Experiments are reported in which a color-matching technique was used to compare the chromatic responses to focal stimuli seen first in isolation and then in the presence of surrounding stimulus arrays of specified luminances and chromaticities and of various degrees of complexity. The results are analyzed in terms of the chromatic response processes of the opponent-colors theory. Chromatic inductions are shown to decrease systematically with decreasing contiguity of focal and surround stimulus areas. For given degrees of contiguity, induced chromatic responses are shown to be opponent to but proportional in magnitude to the mean chromatic activities of the inducing field, and the constant of proportionality decreases as a function of decreasing contiguity.

Journal ArticleDOI
TL;DR: In this paper, the spectral properties of the rare earths have been studied under controlled excitation so that either the spectra of the doubly or triply ionized elements are brought out with maximum intensity.
Abstract: The spectral of the rare earths have been photographed under controlled excitation so that either the spectra of the doubly or triply ionized elements are brought out with maximum intensity. A mild excitation is used in addition to give the first and second spectra for comparison. Some regularities are immediately apparent and vary very gradually through the rare-earth group. The general features of the spectra are discussed in this paper.

Journal ArticleDOI
TL;DR: A visual slit photometer has been built with which the subjective intensity distribution may be evaluated directly and the objective and subjective intensity distributions have been combined to yield the sine-wave response of the visual system.
Abstract: In order to develop a complete specification for the appraisal of the quality of a photographic system by the use of sine-wave response functions, the sine-wave response of the complete visual system must also be known. A method has been worked out for determining the above-mentioned response of the eye. Whenever the eye views a diffuse luminous boundary in which a sudden change of luminance gradient occurs, a bright line appears at the junction of the gradient and the higher luminance, and a dark line at the junction of the gradient and the lower luminance. This phenomenon is a purely subjective one, because physical measurements of the luminances involved show no luminance higher or lower than the two between which the gradient exists.A visual slit photometer has been built with which the subjective intensity distribution may be evaluated directly. By application of Fourier analysis, the objective and subjective intensity distributions have been combined to yield the sine-wave response of the visual system.

Journal ArticleDOI
TL;DR: In this paper, direct images and the radiation patterns of the first few lowest-order dielectric waveguide modes were observed in the visible region of the spectrum for fibers with core and cladding indexes of refraction of 1.56 and 1.52, respectively, and for core diameters from 0.1 to 5.5 μ.
Abstract: The direct images and the radiation patterns of the first few lowest-order dielectric waveguide modes were observed in the visible region of the spectrum for fibers with core and cladding indexes of refraction of 1.56 and 1.52, respectively, and for core diameters from 0.1 to 5.5 μ. The cutoff wavelengths for the observed modes are in reasonably good agreement with theory. Photographs of the modes are shown.

Journal ArticleDOI
TL;DR: In this article, a new Fresnel zone plate was constructed which can focus ultraviolet radiation of any wavelength down to the soft x-ray region, using a set of thin circular gold bands made self supporting by radial struts.
Abstract: A new type of Fresnel zone plate has been constructed which can focus ultraviolet radiation of any wavelength down to the soft x-ray region. It consists of a set of thin circular gold bands made self supporting by radial struts, leaving the transparent zones empty. Experimental tests at 6700, 4358, and 2537 A showed that the theoretical minimum angular resolution obeys the Rayleigh criterion, sinθmin=1.22λ/D. The diameter of the zone plate is D=0.26 cm and contains 19 opaque zones, the narrowest of which measured about 20 μ across. The zone plate was better than the optimum pinhole in resolution by a factor of about 6 and in speed by a factor of 40. The zone plate produced pictures that compared favorably with those made with a lens of similar focal length and aperture. The lens was about 20 times faster than the zone plate at 4358 A, but at 1000 A the zone plate would have been far faster than the lens. Focusing tests are contemplated at 1000 A and at 100 A where lenses and mirrors, the conventional image-forming devices, may fail. The angular resolution at 2537 A was close to the theoretical value of 1.2×10−4 rad and held over a field of at least 1.75×10−2 rad, which is 2.0 times the angle subtended by the sun’s disk at the earth. A zone plate telescope, operating in the soft x-ray or extreme ultraviolet region, far above the earth’s atmosphere in an orbiting satellite, now seems possible.

Journal ArticleDOI
TL;DR: In this paper, the solution for the scattering of radiant energy in the form of electromagnetic waves by concentric isotropic infinitely long circular cylinders is given for the incident energy traveling perpendicular to the cylinder axis.
Abstract: The solution for the scattering of radiant energy in the form of electromagnetic waves by concentric isotropic infinitely long circular cylinders is given for the incident energy traveling perpendicular to the cylinder axis.

Journal ArticleDOI
L. Mandel1
TL;DR: In this article, the authors examined the conditions under which the normalized coherence function γ(x 1,x 2,τ) at two points x 1 and x 2 in an optical field, is reducible to the product of a function of x 1, x 2 and a function τ leading to the concept of cross spectral purity.
Abstract: An examination of the conditions under which the normalized coherence function γ(x1,x2,τ), at two points x1 and x2 in an optical field, is reducible to the product of a function of x1, x2 and a function of τ leads to the concept of cross spectral purity. Spectrally pure beams of light are characterized by the property that their coherence function is so reducible and, operationally, by the fact that superposition does not affect the spectral distribution. Light beams that do not have this property are called spectrally impure, and it is shown to be characteristic of such beams that the interference fringes exhibit a detailed periodic coloring. A measure of the departure from cross-spectral purity is introduced and evaluated in some special cases. It is shown by an example that spectrally pure and spectrally impure beams of light may be derived from the same source with similar optical components. Moreover, these beams may be identical as regards their intensity, their spectral distribution, and their degree of coherence, and differ only as regards their state of spectral purity.

Journal ArticleDOI
TL;DR: The nature of the drift of the eye during monocular fixation was investigated by recording vertical and horizontal components of eye movements under a variety of viewing conditions, and changing the position of the viewing eye in the head produced systematic shifts in the preferred direction of drift.
Abstract: The nature of the drift of the eye during monocular fixation was investigated by recording vertical and horizontal components of eye movements under a variety of viewing conditions. Extinguishing the fixation mark, or placing it at 30 cm instead of at optical infinity was found to increase the net absolute drift rate, as well as to alter the preferred direction of drift. This suggests, as do some previous findings, that the drift of the eye is at least indirectly influenced by visual factors. Changing the position of the viewing eye in the head produced systematic shifts in the preferred direction of drift. The relationship of these findings to various aspects of monocular and binocular fixation were discussed.

Journal ArticleDOI
TL;DR: In this paper, a set of computations of exact Mie functions related to the scattering of electromagnetic waves on dielectric and partially absorbing spheres is described, and the effects of increased absorption index on the extinction and absorption cross section, on the complex amplitude, and on the intensity and polarization of the scattered flux are illustrated by means of diagrams.
Abstract: A new set of computations of the exact Mie functions, related to the scattering of electromagnetic waves on dielectric and partially absorbing spheres, is described. Numerical results with sufficient accuracy and detail in size and angular variation were obtained by means of the IBM-704 computer system for a set of complex indexes of refraction and size ranges mainly corresponding to atmospheric particles illuminated by visible and infrared radiation. The effects of increased absorption index on the extinction and absorption cross section, on the complex amplitude, and on the intensity and polarization of the scattered flux are illustrated by means of diagrams.

Journal ArticleDOI
TL;DR: Waveguide modal patterns have been observed in retinal receptors of rat, monkey, and human eyes and Phenomena characteristically occurring in dielectric waveguides have been noted.
Abstract: Waveguide modal patterns have been observed in retinal receptors of rat, monkey, and human eyes Phenomena characteristically occurring in dielectric waveguides have been noted That aspect considered here is the appearance of different (or combinations of different) hues when the retina is irradiated with white light of a xenon arc and the receptor outer segments are viewed The distribution varies to some degree with angle of incidence of the radiant energy, and the phenomenon is present in both rods and cones It is demonstrated in freshly obtained normal human and monkey central foveal areas and in some peripheral retinal receptors Some implications of these findings are discussed

Journal ArticleDOI
TL;DR: A relatively simple model of the first two links in the visual receptor system is proposed in order to explain the data reported in Part I on amplitude sensitivity to sinusoidally flickering stimuli at photopic adaptation levels of white light.
Abstract: A relatively simple model of the first two links in the visual receptor system is proposed in order to explain the data reported in Part I on amplitude sensitivity to sinusoidally flickering stimuli at photopic adaptation levels of white light [ J Opt Soc Am51, 422 ( 1960)] The model consists of a linear filtering stage followed by a nonlinear pulse-encoding stage The first stage is regarded as essentially “noiseless” at photopic levels; amplitude thresholds are treated as thresholds for the transmission of variable intervals between pulses With the aid of the model, suprathreshold responses can be inferred from the measured threshold behavior In this way, transient responses comparable with various other psychophysical, neural, and electroretinographic data are predicted; the resulting agreement is considered fairly good in view of the parsimony of the proposed model

Journal ArticleDOI
TL;DR: A method for determining optical cross sections, based on finding the point of intersection of the low and high-density asymptotes of an intensity-density curve, is extended to elements of low ionization potentials as discussed by the authors.
Abstract: A method for determining optical cross sections, based on finding the point of intersection of the low- and high-density asymptotes of an intensity-density curve, is extended to elements of low ionization potentials. These elements suffer partial thermal ionization in the flame gases at the relatively high temperatures of 2500° and 2760°K which are used as spectroscopic light sources. Since the degree of ionization of the carrier atoms depends on their partial pressure, the intensity-density curves may be distorted. This difficulty is overcome by increasing the concentration of electrons in the flame gases and thereby shifting the ionization equilibrium to the side of neutral atoms. For the alkaline earth elements the existence of equilibrium ionization is tested for by direct, independent measurements of the partial pressures Avhich enter into the Saha equilibrium quotient. Optical cross sections are measured for the resonance lines of Li, Na, K, Rb, Cs, Ca, Sr, and Ba. The values for the alkalis exhibit a moderate increase with atomic weight which is in accordance with the Weisskopf-Lindholm theory of impact broadening.

Journal ArticleDOI
TL;DR: In this paper, it was shown that at a low luminance level (<5 photons) and in the low-frequency region (<2 cps), when under the special visual conditions no attenuation in the system occurs and with a symmetrical luminance variation such as a sinusoidal modulation or a square-wave modulation with a 1:1 on-off ratio, half the crest-to-trough value of the percentage variation at flicker fusion equals the internal threshold value r0.
Abstract: With two electrical analogs of the brightness system it is shown that at a low luminance level (<5 photons) and in the low-frequency region (<2 cps), when under the special visual conditions no attenuation in the system occurs and with a symmetrical luminance variation such as a sinusoidal modulation or a square-wave modulation with a 1:1 on-off ratio, half the crest-to-trough value of the percentage variation at flicker fusion equals the internal threshold value r0; but with an asymmetrical variation such as a square-wave modulation with a 1:3 on-off ratio, it is the crest value of the periodical percentage variation above the mean luminance level which at flicker fusion equals the internal threshold value r0. At high luminance levels an overshoot in the low-frequency region occurs with both forms of square-wave modulation in accordance with the shape of the attenuation characteristic (AC) of the system under the experimental circumstances. At the steep slope of the ACs for the whole luminance range in cone vision, half the crest-to-trough value of the Fourier fundamental percentage variation at the site of the threshold mechanism located anywhere in the system, equals the internal threshold value r0 at flicker fusion.

Journal ArticleDOI
Leo Young1
TL;DR: In this article, the synthesis of multilayer dielectric films as antireflection coatings over any specified frequency band has not been attempted before, and the design procedure (synthesis) described herein leads to the best possible antireslection films, but demands precisely controlled materials with certain refractive indices.
Abstract: The synthesis (as opposed to analysis) of multilayer dielectric films as antireflection coatings over any specified frequency band has not been attempted before. The similarity with transmission lines, which can be synthesized as multisection quarter-wave transformers to minimize reflection over any prescribed frequency band, is utilized by applying recently developed synthesis procedures for quarter-wave transformers to the synthesis of multiple antireflection films. [ See O. S. Heavens , Optical Properties of Thin Solid Films ( Academic Press, Inc., New York, 1955); and P. J. Leurgans , J. Opt. Soc. Am.41, 714 ( 1951).] A brief review of network synthesis is given, leading up to the synthesis of quarter-wave transformers and multilayer films. Numerical tables are presented in this paper from which antireflection coatings of up to four layers can be designed by interpolation. The design procedure (synthesis) described herein leads to the best possible antireflection films, but demands precisely controlled materials with certain refractive indices. It is hoped that this paper will help to promote the development of such materials, and will encourage opticists to try experimentally for the optimum performances possible in theory.

Journal ArticleDOI
TL;DR: In this paper, the angular distribution of the emergent light from straight cylindrical fibers of circular cross section has been derived and numerically evaluated, and the loss of light due to imperfect reflections, bulk absorption, and Fresnel reflections, are included in the formulation.
Abstract: Equations which describe the flux transmitted and the angular distribution of the emergent light from straight cylindrical fibers of circular cross section have been derived and numerically evaluated. Loss of light due to imperfect reflections, bulk absorption, and Fresnel reflections, are included in the formulation. All skew rays in the fiber have been considered in these calculations.Measurements of the attenuation and angular distribution of the emitted light from plastic scintillating fibers have been made. From the theoretical equations it has been deduced that these fibers are characterized by an internal reflectivity of 0.993±0.002 and an absorption coefficient of 0.015±0.003 cm−1.Measurements of the light transmitted by single-clad glass fibers indicate that these fibers are characterized by an internal reflectivity of 0.9993±0.0002 and an absorption coefficient of the order of 10−4 cm−1. Some experimental data on glass fiber bundles also are included.

Journal ArticleDOI
TL;DR: The results for four subjects show that with both colors and all areas the product of threshold intensity and time is a constant for all exposure times up to 100 msec, in direct contradiction to previous findings.
Abstract: An experimental determination has been made of the effect of increasing size on the time interval over which the product of intensity and time is a constant Past research with white-light stimuli has shown It constancy to break down at progressively shorter exposure times as the diameter of a circular test field is increased up to 3 deg This experiment employed circular fields of red and blue-green monochromatic light centered in the peripheral retina 20 deg from the point of fixation Thresholds for durations from 313 to 1000 msec and areas of 343 min, 1 deg, 3 deg, and 8 deg were obtained by the method of constants The results for four subjects show that with both colors and all areas the product of threshold intensity and time is a constant for all exposure times up to 100 msec This is in direct contradiction to previous findings That these differences may depend on the spectral quality of the test light is discussed, as are the theoretical implications of the findings


Journal ArticleDOI
TL;DR: The computer has been used to detect electroretinograms which were used in an investigation of area-luminance and stray-light effects within the eye and the waveform of the response was found to depend on both the color and the position of the stimulus on the retina.
Abstract: The operation of a computer which averages low-amplitude electroretinograms is described. The computer has been used to detect electroretinograms which were recorded in an investigation of area-luminance and stray-light effects within the eye. Large test stimuli were found to be more effective than small for producing responses of fixed size. Although the observers reported that the stimulus spread over much of the retina larger photopic responses appeared when the stimulus was centered on the fovea than on neighboring areas. The waveform of the response was found to depend on both the color and the position of the stimulus on the retina.

Journal ArticleDOI
TL;DR: In this article, a discussion is given of the effect of mechanical errors in a grating drive on the accuracy with which line frequencies can be measured, and it is shown that it is highly improbable that a mechanical device used to rotate a diffraction grating can be constructed with sufficient precision so that the line-frequency error will be determined by the optical information observable in the near infrared spectrum.
Abstract: A discussion is given of the effect of mechanical errors in a grating drive on the accuracy with which line frequencies can be measured. It is shown that it is highly improbable that a mechanical device used to rotate a diffraction grating can be constructed with sufficient precision so that the line-frequency error will be determined by the optical information observable in the near infrared spectrum. By making use of the echelle spectrograph 67 lines of the 001–000 absorption band of HCN have been measured. Almost 400 lines from five N2O absorption bands arising from the ground state of the molecule have been measured. In addition, 11 lines from the 1–0 fundamental band of CO have been measured in order to determine ν0 for this band. In all cases only band lines have been measured which appear to be free of blends. The molecular constants of the above bands have been determined by making use of the combination relationships applying least-squares methods to the data. The line frequencies have then been calculated to four decimal places and presented in tables. The tables contain over 600 line frequencies. We believe the calculated line frequencies (lines free of blends) have an absolute accuracy of about 1 part in 5×106 and a relative accuracy referring to lines within a given band somewhat greater.