Showing papers on "Laser linewidth published in 1973"
TL;DR: In this paper, an expression for the linewidth of phonons associated to a disorder mechanism in crystals is deduced, and a new view point to the application of fluctuation-dissipation theorem for order-disorder crystals is presented.
107 citations
TL;DR: In this paper, X-ray scattering studies in single-crystal beryllium reveal an anisotropy in both the plasmon dispersion and linewidth, and by comparing the data with random-phase approximation-type theory which includes band structure, they can begin to separate the contributions from the lattice and from true many-body interactions to the temporally and spatially dependent response of an interacting electron gas at metallic densities.
Abstract: X-ray scattering studies in single-crystal beryllium reveal for the first time an anisotropy in both the plasmon dispersion and linewidth. By comparing the data with random-phase-approximation-type theory which includes band structure, we can begin to separate the contributions from the lattice and from the true many-body interactions to the temporally and spatially dependent response of an interacting electron gas at metallic densities.
66 citations
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TL;DR: In this paper, the ESR signal in GeS2 was a single Gaussian line with linewidth of ca. 15 G. The signal disappeared by addition of 5 molar % arsenic.
58 citations
TL;DR: In this article, a single mode cw dye laser was used to investigate the hyperfine splittings of the Na D1 and D2 lines of a Na D2 line, where the light of the laser was scattered by the atoms of an atomic beam.
Abstract: The hyperfine splittings of the Na D1 and D2 lines were investigated using a single mode cw dye laser. The light of the laser was scattered by the atoms of an atomic beam and the fluorescent light was observed as the frequency of the laser was tuned across the D lines. The Doppler width of the atomic beam was reduced to about 2.5 MHz so that the absorption width of the atoms of the beam was essentially determined by the natural width of the 32P1/2 and 32P3/2 levels, which is about 10 MHz. Since the linewidth observed for the hyperfine transitions was 30 MHz, most of the hyperfine components of the D1 and D2 lines could be resolved. In another experiment the frequency of the dye laser was locked to a hyperfine transition of the D1 line. The observed variation of the output frequency of the dye laser was less than ±1.5 MHz. In addition, the intensity of the dye laser was controlled to about 10−3, using an electro-optically variable transmission filter.
53 citations
TL;DR: By utilizing a dispersive element in an external cavity, this article found it possible for pulsed room-temperature GaAs diodes to emit high output power (3 W) into a narrow linewidth (04 A).
Abstract: By utilizing a dispersive element in an external cavity, we find it possible for pulsed room‐temperature GaAs diodes to emit high output power (3 W) into a narrow linewidth (04 A) This narrow‐band output is continuously tunable over an ∼ 100‐A range with only a moderate variation in output power Significantly, these qualities are preserved even at high output power densities (3 × 106 W/cm2)
47 citations
TL;DR: In this paper, a small-signal gain technique has been used to measure the lineshape of spontaneous spin-flip Raman scattering as a function of magnetic field (H = 0.5-10 kG).
40 citations
TL;DR: In this paper, the linewidth of a cw-single-mode tunable dye laser has been investigated and it was found that the linwidth is determined by microscopic velocity fluctuations of the turbulent flow within the dye cell of the laser and by fluctuations of pump power.
Abstract: The linewidth of a cw-single-mode tunable dye laser has been investigated. It was found that the linewidth is determined by microscopic velocity fluctuations of the turbulent flow within the dye cell of the laser and by fluctuations of the pump power. The linewidth is further influenced by mechanical disturbances and by temperature fluctuations of the dye solution. The results of the investigations made it possible to achieve a reduction of the velocity fluctuations. It is shown that under adequate operating conditions the free-running dye laser has a linewidth of 2 MHz.
39 citations
01 Jan 1973
39 citations
TL;DR: In this paper, a vector magnetometer was built utilizing the n = 0, p = 1 parametric resonance associated with zero-field level crossings in the optically pumped 23S 1 level of He4.
Abstract: A vector magnetometer has been built utilizing the n = 0, p = 1 parametric resonance associated with zero-field level crossings in the optically pumped 23S 1 level of He4. The principles of operation are discussed and performance is described. The parametric resonance signal-to-noise ratio is 3.5 × 104in a 0.5 Hz noise bandwidth. The linewidth is 9.7 × 10-4G. Techniques for optimizing the sensitivity are discussed, and the sensitivity of the instrument is demonstrated by placing the sensor inside a superconducting magnetic shield and applying calibration signals, The peak-to-peak noise level is 1 × 10-8G. The use of parametric resonance instruments to measure interplanetary and geomagnetic fields is discussed.
37 citations
TL;DR: In this paper, the authors present results of theoretical calculations and supporting experiments which determine optimum settings for spectrometers used in the "side-on" viewing mode to observe spectral lines emitted by fast-beam sources.
35 citations
TL;DR: In this article, the operation of a low-field spin-flip Raman (SFR) laser utilizing a closed-cycle refrigerator is reported, achieving an SFR gain in InSb that gives a spontaneous SFR linewidth as narrow as ∼ 400 MHz.
Abstract: The operation of a low‐field spin‐flip Raman (SFR) laser utilizing a closed‐cycle refrigerator is reported. SFR laser conversion efficiencies as high as 80% have been observed enabling us to observe the operation of a IV Stokes SFR laser for the first time. SFR gain in InSb is measured that gives a spontaneous SFR linewidth as narrow as ∼ 400 MHz.
TL;DR: In this article, the effect of magnetoelastic interactions on ferromagnetic resonance in thin films was investigated and it was shown that the magneto-elasticity has an appreciable effect on the resonance linewidth only in the cases where an elastic wave undergoes a thickness resonance near the ferromagneto-resonance frequency.
Abstract: We have undertaken a theoretical study of the effect of magnetoelastic interactions on ferromagnetic resonance in thin films as a possible mechanism for an appreciable anisotropy in resonance linewidth. This study is based on a formalism developed by Tiersten, which is exact within the framework of the quasistatic approximation. The resonance frequency and linewidth are calculated from the simultaneous solution of the coupled magnetoelastic equations of motion under various magnetic and elastic boundary conditions. We find that the magnetoelasticity has an appreciable effect on the resonance linewidth only in the cases where an elastic wave undergoes a thickness resonance near the ferromagnetic-resonance frequency, which we call the "ferromagnetoelastic resonance condition." The above facts have made it possible to develop a self-consistent approximate method, which greatly simplifies the mathematical treatment without sacrificing the physical model. The agreement between the approximate and exact calculations is excellent.
TL;DR: In this article, the two-photon ionization of molecular cesium as a continuous function of laser wavelength in the 6200-6600-AA{} region with a tunable dye laser having a 0.18-${\mathrm{Cm}}^{\ensuremath{-}1}$ linewidth was observed.
Abstract: This paper reports the observation of the two-photon ionization of molecular cesium as a continuous function of laser wavelength in the 6200-6600-\AA{} region with a tunable dye laser having a 0.18-${\mathrm{Cm}}^{\ensuremath{-}1}$ linewidth. To the author's knowledge, it serves to illustrate the first extension to neutral molecular species of the important techniques of resonant multiphoton photodetachment spectroscopy. The resulting two-photon photoionization spectrum is intepreted in terms of the vibrational structure of the resonant intermediate molecular state.
TL;DR: In this paper, the ESR signal of Cr 3+ ions in triglycine-sulphate was observed and it was found that a pair of lines gradually approach to each other with increasing temperature in the ferroelectric phase and converge at the Curie temperature.
Abstract: We observed the ESR signal of Cr 3+ ions in triglycine-sulphate. It is found that a pair of lines gradually approach to each other with increasing temperature in the ferroelectric phase and converge at the Curie temperature. The results are interpreted by using the concept of motional narrowing on the basis of the model of order-disorder type. The linewidth for the applied magnetic field nearly parallel to the principal axis z shows an anomalous increase near the Curie temperature. The critical exponent of the linewidth in the ferroelectric region is determined to be 0.5 in the vicinity of the Curie temperature and to be 2.0 far from the Curie temperature.
TL;DR: In this paper, the rate equations for the molecular state densities and mode photon densities were set up for a flashlamp-pumped tunable dye laser and the untuned dye laser line shape was also calculated.
Abstract: The rate equations for the molecular state densities and mode photon densities are set up for a flashlamp-pumped tunable dye laser. These are solved numerically for a typical rhodamine 6G laser tuned by a Fabry-Perot etalon and the results compared with experiment. The untuned dye laser line shape is also calculated and compared with experiment.
TL;DR: In this article, the hyperfine structure of the Na D 2 -line was investigated in a fluorescence experiment involving a narrow band tunable dye laser and a highly collimated atomic beam.
TL;DR: Continuously tunable cw diode lasers that produce narrow-line (1 − to 10 −MHz linewidth) radiation in the 3.5 −μm region have been fabricated from Pb0.98Cd0.02S.
Abstract: Continuously tunable cw diode lasers that produce narrow‐line (1‐ to 10‐MHz linewidth) radiation in the 3.5‐μm region have been fabricated from Pb0.98Cd0.02S. Lasers operating at 10–20 K produced more than 1 mW of cw power distributed among several modes which could be tuned continuously > 1 cm−1 by adjusting the laser current. A spectral range of 30 cm−1 could be covered over the full operating range. Ultrahigh‐resolution (10−5 cm−1) spectra of H2CO have been obtained to demonstrate the potential application of these lasers to the identification of organic molecules by spectroscopy of their C–H stretch absorption bands.
TL;DR: In this paper, the hyperfine structure of the 3 2 P 3 2 state of sodium has been resolved, for the first time with a purely optical technique, using a cw tunable dye laser with very high frequency stability in conjunction with a Rabi type sodium atomic beam.
TL;DR: In this article, the rotational quantum number (J,K) dependence of the linewidth parameters for sulfur dioxide (SO2) at 300 °K was investigated and the Anderson collision theory with appropriate modifications for dominant dipole-dipole interaction between these molecules.
Abstract: A systematic study was made of the rotational quantum number (J,K) dependence of the linewidth parameters for sulfur dioxide (SO2) at 300 °K. Linewidth parameters were used to calculate effective hard‐sphere collision diameters for SO2 over the pressure range 0.001 ≤ P ≤ 0.06 torr. Linewidth parameters were calculated using the Anderson collision theory with appropriate modifications for dominant dipole‐dipole interaction between these molecules. These calculations compare favorably with the experimental values obtained. The linewidth parameter trend was explored for transitions Δ J=1, 0≤ J ≤ 43, with all transitions lying within the frequency range of the instrument 4–80 GHz.
TL;DR: In this paper, the gain line profile of the P(18) line of the 00°1 → 10°0 vibrational band of CO2 is reported between 1 and 12 Torr.
Abstract: High‐resolution frequency‐measuring spectroscopy techniques have been extended to the infrared region for the first time. The initial data obtained from this spectrometer are gain versus frequency for CO2 transitions. The gain line profile of the P(18) line of the 00°1 → 10°0 vibrational band of CO2 is reported between 1 and 12 Torr. The slope of the collison contribution to the linewidth is determined to be 4.46 MHz/Torr at 296°K in a mixture of 14% CO2, 17% N2, and 69% He.
TL;DR: In this paper, the frequency tuning of a high-pressure CO 2 laser with an e-beam preionization was achieved for the first time, and the laser linewidth in this case is less than 0.01 cm −1.
TL;DR: In this paper, an oscillator-amplifier dye laser pumped by a single giant-pulse ruby laser is described, which allows production of a tuneable 5 MW, 30 nsec pulse without damaging the intra-cavity echelle which is used to achieve the 0.05 nm linewidth.
TL;DR: In this paper, the authors presented a formal treatment of ferromagnetic-netoelastic resonance (FMER) in thin films and applied it to the calculation of resonance lines of nickel at room temperature and at 25.92 GHz, a $K$-band frequency.
Abstract: In Paper I we presented a formal treatment of ferromagnetoelastic resonance (FMER) in thin films. In the present paper, this method is applied to the calculation of resonance lines of nickel at room temperature and at 25.92 GHz, a $K$-band frequency. It is shown that the FMER conditions are the following: (i) The film thickness nearly equals an odd-integral number of half-wavelengths of the elastic wave at the ferromagnetic-resonance frequency under the spin-unpinned and traction-free boundary conditions, or under the spin-pinned and traction-free boundary conditions; (ii) the film thickness nearly equals an even-integral number of half-wavelengths of the elastic wave under the spin-pinned and deformation-free boundary conditions. The thickness range over which the linewidth enhancement occurs is about 3% of the FMER thickness. The effect of the elastic damping on the linewidth enhancement is discussed. The angular dependence of the linewidth is examined in detail, along with the resonance-frequency shift and line shape. Finally, the relationship of the FMER problem to that of phonon generation is discussed briefly.
TL;DR: Very high resolution measurements of hyperfine structure on the P(13) and R(15), 43−0, 3 gp 0 + u ← 1 Σ g + transitions in iodine 127 were made using laser molecular beam spectroscopy as mentioned in this paper.
TL;DR: In this paper, the spectral change with excitation and the linewidth of room temperature (Ga Al)As-Ga As heterostructure lasers was studied and it was shown that the laser line is homogeneously broadened and the diffusion of the inverted population plays an effective role in the single-mode operation at room temperature.
Abstract: Experimental studies have been made of the spectral change with excitation and the linewidth of room temperature (Ga Al)As-Ga As heterostructure lasers. The lasers with stripe geometry configuration show uniform near-field patterns and single axial mode operations in relatively wide ranges of current levels. Continuous output powers of several to 20 mW (from one facet) have been obtained under single axial mode operations at current levels below 500 mA. Experimental data on excitation-dependent spectral change indicate that the laser line is homogeneously broadened and the diffusion of the inverted population plays an effective role in the single-mode operation at room temperature. Observations of the interference fringes with a Fabry-Perot etalon having plate separations of the centimeter range revealed the frequency variation with time under continuous operation. Probably this effect is the reflection of a very large temperature coefficient of the laser frequency at room temperature, Full linewidths shown in the photographs of the fringes taken with exposure times of about 1 s were less than several hundred megahertz, which is compared with the theoretical estimate of a few megahertz at several milliwatts.
TL;DR: In this article, the influence of molecular C=O reorientation in urea on the 14N PNQR linewidth and spin-lattice relaxation time is presented.
Abstract: The theory of the influence of molecular C=O reorientation in urea on the 14N PNQR linewidth and spin‐lattice relaxation time is presented. Pulse techniques are used to measure the inverse linewidth, spin phase memory time and spin‐lattice relaxation time of the two high frequency transitions at several temperatures. The relaxation time T1z of the low‐lying transition is measured using double radiation methods. At room temperature the spin‐lattice relaxation times are highly anisotropic, with T1z three orders of magnitude shorter than T1x and T1y. The experimental results are consistent with a molecular C=O reorientation. The activation energy for this motion is ΔE=11.7±2 kcal/mole.
TL;DR: In this paper, a Michelson-type mode selector was used for single-mode operation of a flashlamp pumped dye laser with an output power of 1 kW with a linewidth of 0.05 pm.
Abstract: After efficient spectral narrowing with an interference filter and two succesive Fabry‐Perot etalons single‐mode operation of a flashlamp pumped dye laser has been achieved using a Michelson‐type mode selector as proposed by Fox and Smith. Typical output powers of 1 kW with a linewidth of 0.05 pm have been obtained.
01 Dec 1973
TL;DR: In this paper, the authors investigate the operating parameters of waveguide CO2 laser and demonstrate single mode operation of a CO2 waveguide laser over a pressure broadened linewidth.
Abstract: : The program is an exploratory study on waveguide gas lasers in general, with an emphasis on waveguide CO2 lasers. The goals of the program were to investigate the operating parameters of waveguide gas lasers, to demonstrate single mode operation of a CO2 waveguide laser over the pressure broadened linewidth, to mode lock the CO2 waveguide laser, and to study mode control of waveguide lasers. Experiments on frequency tuning of the waveguide CO2 laser were performed. An extensive theoretical treatment has been performed on resonators for waveguide lasers. Using a matrix diagonalization technique, the resonator losses and resonator modes for waveguide resonators have been determined. Specific resonator configurations were found which are specifically designed for high transverse mode selectivity.