Showing papers on "Laser linewidth published in 1971"
TL;DR: Dye laser electronic tuning by inserting calcium-molybdenum oxide acousto-optic filter into cavity is described in this article. But the authors do not discuss the use of color information.
Abstract: Dye laser electronic tuning by inserting calcium-molybdenum oxide acousto-optic filter into cavity
113 citations
TL;DR: Absorption spectra enhancement by organic dye laser quenching, considering applications for absorbing species spectroscopic detection was discussed in this article, where the authors proposed a method to enhance the spectra with organic dye.
Abstract: Absorption spectra enhancement by organic dye laser quenching, considering applications for absorbing species spectroscopic detection
108 citations
TL;DR: The P(9) fundamental infrared absorption line of carbon monoxide at 2107.4 cm−1 has been studied with high resolution using a cw current tunable PbS0.82Se0.18 diode laser as discussed by the authors.
Abstract: The P(9) fundamental infrared absorption line of carbon monoxide at 2107.4 cm−1 has been studied with high resolution using a cw current tunable PbS0.82Se0.18 diode laser. Both the Doppler linewidth of 150 MHz and the absorption coefficient at line center of 2.1 cm−1/Torr at room temperature have been measured directly for the first time with an estimated resolution of 1% of the linewidth.
53 citations
TL;DR: In this paper, the power-versus-wavelength characteristic for a high-power, continuously tunable far-infrared source has been experimentally determined and compared with theory, using a Q-switched ruby laser as the pump and stimulated polariton scattering in the crystal LiNbO3 as the scattering mechanism.
Abstract: The power‐versus‐wavelength characteristic for a high‐power, continuously tunable far‐infrared source has been experimentally determined and compared with theory. Utilizing a Q‐switched ruby laser as the pump and stimulated polariton scattering in the crystal LiNbO3 as the scattering mechanism, peak powers outside the crystal of ∼ 3 W at 200 μ are observed without crystal damage. Linewidth measurements indicate a bandwidth of < 0.5 cm−1 for the radiation over the observed tuning range 66–200 μ.
50 citations
TL;DR: In this paper, a prism positioned at a very high angle of incidence approaching 90 o in the optical cavity of a rhodamine 6-G dye laser excited by a pulsed nitrogen laser leads to improvement in linewidth reduction.
49 citations
TL;DR: In this paper, the broadening of the phonon modes produced by lattice strains on Xe ion implantation is measured for GaAs and shown to increase with fluence.
Abstract: We report measurements of Raman scattering in ion‐implanted semiconductors. The broadening of the phonon modes produced by lattice strains on Xe ion implantation is measured for GaAs. The measurements show pronounced effects on the linewidth at moderate fluence levels and demonstrate that Raman scattering can provide a sensitive technique for probing stresses introduced by ion implantation. At higher‐fluence levels where the material begins to transform from crystalline to amorphous, the linewidth is found to increase rapidly with fluence.
37 citations
TL;DR: In this article, temperature effects on long wavelength photon frequency and linewidth in diamond, using Raman scattering techniques, were investigated in a diamond environment using temperature-sensitive laser rangefinders.
Abstract: Temperature effects on long wavelength photon frequency and linewidth in diamond, using Raman scattering techniques
37 citations
TL;DR: In this paper, the Doppler shift of light emitted by fast ion beams was used to cancel the broadening introduced by opening the spectrometer entrance slit and wide slits were used to increase collected flux with minimal increase in recorded linewidth.
Abstract: We use the Doppler shift of light emitted by fast ion beams to cancel the broadening introduced by opening the spectrometer entrance slit Hence, wide slits are used to increase collected flux with minimal increase in recorded linewidth
29 citations
TL;DR: In this paper, an efficient internally frequency-doubled mode-locked Nd:YAG laser has been operated, which makes use of an intracavity harmonic mirror to produce 1.5 W of 0.53μ power in the output beam.
Abstract: An efficient internally frequency‐doubled mode‐locked Nd:YAG laser has been operated. An interaction between the intracavity harmonic generation and mode locking, which results in a lengthening of the mode‐locked pulse and a corresponding decrease in fundamental circulating power, has been observed with this laser. The laser makes use of an intracavity harmonic mirror to produce 1.5 W of 0.53‐μ power in the output beam. A significant decrease in laser noise is observed when the laser is mode locked.
28 citations
TL;DR: In this article, a detailed experimental study of laser signature as a function of laser mirror distance variations is reported for small sealed low-power CO 2 lasers (≈ 1 watt) of the type useful in laser communication.
Abstract: A detailed experimental study of laser signature as a function of laser mirror distance variations is reported. This was done for small sealed low-power CO 2 lasers (≈ 1 watt) of the type useful in laser communication. It is shown that most laser-output profiles change drastically from half-wavelength to half-wavelength except the strong P(20) line, which seems to remain relatively constant. Frequency width is given for many of the laser output profiles appearing in the various signatures observed. Line competition is also discussed.
26 citations
TL;DR: In this article, the molecular quadrupole moment of O2 from linewidth data for broadening of NH3 inversion lines by O2 was obtained for the microwave absorption lines by collisions involving O2.
Abstract: The pressure broadening of microwave absorption lines by collisions involving O2 has been investigated using a method presented earlier for analyzing and evaluating microwave linewidth parameters under conditions where impact‐theory assumptions are valid. A value of (1.16 ± 0.12) D· A was obtained for the molecular quadrupole moment of O2 from linewidth data for broadening of NH3 inversion lines by O2. This value is in reasonably good agreement with values determined by other methods, and should constitute an upper limit to the true value since only dipole–quadrupole interaction was considered in the linewidth calculations, This value of the molecular quadrupole moment of O2 was used to calculate linewidth parameters for H2O–O2 broadening, OCS–O2 broadening, N2O–O2 broadening, O2–O2 self‐broadening, and the broadening of the 9– line of O2 by various foreign gases. These results are in general smaller than the experimental values, suggesting that the effects of higher‐order interactions are important in co...
TL;DR: In this article, the first pure, undiluted rare-earth compound laser was obtained from a single crystal of HoF3 at liquid-nitrogen temperatures, with a spontaneous linewidth of 1.5 cm−1 for the laser transition.
Abstract: Efficient laser emission of Ho3+ at 2μ has been obtained from a single crystal of HoF3 at liquid‐nitrogen temperatures. This is the first pure, undiluted rare‐earth compound laser. Fluorescence and absorption spectra indicated a spontaneous linewidth of 1.5 cm−1 for the laser transition. The fluorescence lifetime at 77°K was 2.6 msec, or 29% of the radiative lifetime as measured in dilution in an isomorphic host. The laser threshold for a 15‐mm rod was about 1 J.
TL;DR: In this paper, the authors show that polycrystalline garnets with room-temperature X-band linewidth values below 4 Oe can reproducibly be prepared by reducing magnetocrystalline anisotropy and porosity to about zero values.
Abstract: Polycrystalline garnets with room-temperature X -band linewidth values below 4 Oe can reproducibly be prepared by reducing magnetocrystalline anisotropy and porosity to about zero values. The lowest linewidth which has been measured so far is \DeltaH = 1.7 Oe. Reduction of anisotropy can be accomplished by substitution of octahedral Fe3+ions by nonrelaxing ions of large enough ionic radius (In3+, Zr4+, Sn4+). Theoretical density and phase purity is achieved by simultaneous substitution of Y3+ions by Ca2+ions in combination with a tetravalention (Ge4+, Si4+, Zr4+, Sn4+) for charge compensation. In the different compositional series studied, low linewidth values can be obtained for a magnetization range of 1950 to 250 G. As a consequence of the phase purity and the complete absence of porosity, the perfect polycrystalline samples become transparent in the infrared "window" region of the Fe garnets.
TL;DR: In this article, the linear relationship between spin wave linewidth and second phase inclusions in polycrystalline YIG samples was investigated and it was suggested that in porous specimens, the average size of the pores may affect the spin wave linearity and that this effect is similar to the transit-time effect produced by finite grain sizes.
Abstract: Nonmagnetic second‐phase inclusions of two different average sizes (2.5 ± 0.5 and 1.2 ± 0.5 μ m) were produced in specimens of polycrystalline YIG. A dependence of spin‐wave linewidth on inclusion size was observed. The linear relationship between spin‐wave linewidth and the concentration of second‐phase inclusions was dependent on the wave vector k. At k ≈ 2 × 105 cm−1, the relationship was 0.15 Oe and 0.075 Oe per % second‐phase concentration for the samples with the smaller and larger inclusions, respectively. It is suggested that in porous specimens the average size of the pores may affect the spin‐wave linewidth and that this effect is similar to the transit‐time effect produced by finite grain sizes.
TL;DR: In this paper, the emission linewidth of a Nb-Nb Josephson point contact is measured vs dc current and compared with the theoretical predictions of Stephen and Scalapino.
Abstract: The emission linewidth of a Nb–Nb Josephson point contact is measured vs dc current and compared with the theoretical predictions of Stephen and Scalapino. The good agreement between experimental results and theory even for high junction currents, the pair current being generally much larger than the quasiparticle current, indicates that Stephen's theory gives a fair picture of the pair‐current noise properties in point‐contact junctions.
TL;DR: In this paper, the classical turning points for the curve contained between the upper parts of the repulsive and attractive potential functions may be deduced for an experimental pattern of linewidths.
Abstract: Analytical expressions for the predissociation linewidth as a function of vibrational and rotational state are obtained by a semiclassical (WKB) method It is then shown how the classical turning points for the curve contained between the upper parts of the repulsive and attractive potential functions may be deduced for an experimental pattern of linewidths The theory is successfully applied to data for the A 2Σ+ state of OD
TL;DR: Some interesting theoretical and experimental holographic coherence length curves are presented for a Q-switched laser oscillator and amplifier system.
Abstract: A theoretical treatment of holographic brightness for a gaussian-shaped laser pulse permits a more rigorous consideration of holographic coherence length for single-mode (TEM00q) pulse laser. Three cases are treated: (1) the ideal single frequency pulse laser oscillator; (2) the pulse laser oscillator with frequency sweep; and (3) the pulse laser oscillator with frequency sweep along with the laser amplifier with frequency shift. Some interesting theoretical and experimental holographic coherence length curves are presented for a Q-switched laser oscillator and amplifier system.
TL;DR: In this paper, the Larmor frequency was used to estimate the EPR linewidth at 24.43 GHz near the critical point of MnF2, and it was suggested that the observed frequency dependence near TN is due to breakdown of the usual exchange narrowing condition.
Abstract: EPR linewidth measurements at 24.43 GHz have been made near the critical point TN of MnF2. Comparison with similar measurements at 9 and 35 GHz shows that the EPR linewidth near TN depends on the Larmor frequency, its magnitude at a given temperature being smaller at higher frequencies. This is the first observation of this effect recently predicted by Kawasaki. It is suggested that the observed frequency dependence near TN is due to breakdown of the usual exchange narrowing condition.
TL;DR: Ferromagnetic resonance linewidth measurements were performed at 37.6 GHz on substituted barium ferrite, BaZnx Tix Fe12−2xO19, where x varies from 1.0 to 2.5 in the melt.
Abstract: Ferromagnetic resonance linewidth measurements were performed at 37.6 GHz on substituted barium ferrite, BaZnx Tix Fe12−2xO19, where x varies from 1.0 to 2.5 in the melt. Crystals were synthesized by two growth procedures; a modified pulling technique and a free nucleation method from slow cooling BaO/B2O3 fluxes. The uniaxial anisotropy field Ha varied from 5400 to 11 100 Oe; Tc from 351° to 613°K, making the material of considerable interest for microwave device applications. Cavity perturbation techniques were used with polished spherical samples 15–20 mil in diameter. Variation in values of x have a large effect on the linewidths obtained. The linewidth decreases with increasing x to a minimum at 1.5 and then increases as x exceeds 1.5. At x = 1.5, resonance linewidths of 36 Oe on pulled crystals and 42 Oe on free nucleated crystals were observed.
TL;DR: A theoretical model is developed based on mixing of emission band components which are spaced equidistant and symmetrically about the part of line that corresponds to maximum SHG (Deltak = 0), which agrees well with the observed spectral line narrowing, relatively high experimental conversion efficiency, and experimental tuning curve.
Abstract: A technique is described for producing a continuously tunable uv source using the broadband emission from a dye laser as input to a rotatable KDP crystal. A theoretical model is developed based on mixing of emission band components which are spaced equidistant and symmetrically about the part of line that corresponds to maximum SHG (Δk = 0). This model agrees well with the observed spectral line narrowing, relatively high experimental conversion efficiency, and experimental tuning curve.
TL;DR: In this article, the hyperfine splitting of localized electron resonance in a dilute magnetic alloy was studied and the corresponding eigenvectors were determined, enabling a physical generalization to arbitrary nuclear spin.
Abstract: Phenomenological equations describing the hyperfine splitting of a localized electron resonance in a metal are studied. The transverse susceptibility χ+(ω) is obtained for the case of nuclear spin I=½, and its poles and residues are displayed. The corresponding eigenvectors are determined, enabling a physical generalization to arbitrary nuclear spin. The validity of the generalization procedure is verified by an examination of the generalized susceptibility. The conditions for the observation of the hyperfine splitting in a dilute magnetic alloy are detailed. Three distinct regions are found to be important, depending on the strength of the exchange coupling. Region (1), corresponding to a very weak exchange coupling, exhibits hyperfine splittings of the same character as in an insulator. The linewidth of each hyperfine component equals Δse+ΔsL, where Δse is the second‐order localized‐conduction electron exchange relaxation rate, and ΔsL the localized spin lattice relaxation rate. Region (2) corresponds t...
TL;DR: In this paper, the authors investigated the pumping mechanism of a high-current pulsed CO2 laser and found that there is a time delay of the laser pulse behind the current pulse, which is due to the time required for CO and O to recombine to reach the threshold population for lasing for the particular optical cavity.
Abstract: The pumping mechanism of a high‐current pulsed CO2 laser has been investigated. It was found that there is a time delay of the laser pulse behind the current pulse. From the dependence of the time delay on the plasma parameters, such as electron density, electron temperature, gas temperature, gas pressure, and emission of oxygen atomic line (7771 A), it can be shown that during the current pulse, the CO2 is totally dissociated into CO and O. The subsequent recombinations of CO and O into CO2 are responsible for the pumping of the upper level of the CO2 laser (10.6 and 9.4 μ). The time delay between the current pulse and laser pulse is thought to be due to the time required for CO and O to recombine to reach the threshold population for lasing for the particular optical cavity. The threshold upper level population is obtained by knowing the Q value of the optical cavity, wavelength of the laser line, and linewidth of the radiation line. By equating the amount of CO2 formed during the delay time to the threshold upper laser population, the reaction rate of CO+O→CO2 is thus obtained. The agreement between the rate obtained and previously determined supports the proposed pumping mechanism.
TL;DR: By measuring the beam width and radius of curvature of the wavefront of a He-Ne gas laser, including several higher order modes, the behavior of a laser beam is investigated experimentally.
Abstract: A simple method for measuring the beam parameters of a laser beam, using a hologram, is proposed, and the accuracy is examined. By measuring the beam width and radius of curvature of the wavefront of a He–Ne gas laser, including several higher order modes, the behavior of a laser beam is investigated experimentally. As another application of this method, the phase distribution of the diffracted field from an aperture and a slit illuminated by a laser beam is measured, and the effects of a beam upon the diffracted field are studied experimentally.
TL;DR: In this paper, the effect of a time-varying electric field on the absorption coefficient and refractive index of a molecular gas near an absorption line has been investigated using a density matrix approach.
Abstract: The molecular Stark effect and its application to the modulation of infrared laser radiation have been investigated both theoretically and experimentally. Using a density matrix approach, a quantum mechanical description of the effect of a time-varying electric field on the absorption coefficient and refractive index of a molecular gas near an absorption line has been formulated. For modulation applications a quantity known as the "modulation depth" is of prime importance. Theoretical expressions for the frequency dependence of the modulation depth show that the response to the frequency of a time-varying Stark field is separated into a nondispersive and a dispersive region, depending on whether the modulating frequency is less than or greater than the homogeneous absorption linewidth. Experimental results showing nondispersive modulation at frequencies to 30 MHz are presented. In addition it is shown that the response of modulation depth to Stark field amplitude is separated into linear and nonlinear regions, the field at which nonlinearities begin being determined by the absorption spectrum of the molecule being used.
Patent•
17 Jun 1971TL;DR: In this article, a new type of dye laser in which the dye cell is placed inside a pumping laser resonator is described, and both the dye laser radiation and the pumping laser radiation oscillate inside the same optical cavity.
Abstract: A new type of dye laser in which the dye cell is placed inside a pumping laser resonator is described. Both the dye laser radiation and the pumping laser radiation oscillate inside the same optical cavity. This design has the advantage of automatic alignment of the pumping laser and the pumped laser, as well as the reduction of the thermal problems. In the instance in which the laser frequencies do not differ greatly, automatic mode matching of the pumping laser beam and the pumped laser beam is obtained.