Showing papers on "Tunable laser published in 1971"
TL;DR: In this article, a new technique was presented for obtaining the absorption spectra of small samples and low concentrations of gases, which makes use of currently available sources of wavelength-tunable intense coherent light such as the optical parametric oscillator, dye laser, or tunable diode laser.
Abstract: A new technique is presented for obtaining the absorption spectra of small samples and low concentrations of gases. The technique makes use of currently available sources of wavelength‐tunable intense coherent light such as the optical parametric oscillator, dye laser, or tunable diode laser. The absorbed power is detected by the heating and resultant pressure rise in the absorbing gas. An initial experiment with a 15‐mW He–Ne laser operating at 3.39 μ has shown a sensitivity adequate to measure the absorption of a concentration of 10−8 of methane in nitrogen. It is expected that, with higher‐power sources of tunable ir radiation, it may be possible in the future to detect concentrations of impurities as low as 10−13.
498 citations
TL;DR: In this paper, a simple and rugged electrode structure is described for the production of uniform pulse-excited discharges throughout large volumes at atmospheric pressure, achieving energy densities of 18 mJ/cm3 in a multimode CO2 laser.
Abstract: A simple and rugged electrode structure is described for the production of uniform pulse-excited discharges throughout large volumes at atmospheric pressure. Output energy densities of 18 mJ/cm3 have been achieved in a multimode CO2 laser. The performance is compared with that of a novel mesh-cathode electrode system.
104 citations
TL;DR: In this paper, a capillary-guide liquid laser longitudinally pumped with Rhodamine 6G and several other dyes has been observed to exhibit permanent bleaching of the dyes, which is shown to present a severe limitation to the operation of nonflowing continuously excited dye lasers.
Abstract: Rapid bleaching of Rhodamine 6G and several other dyes has been observed in capillary-guide liquid lasers longitudinally pumped at \lambda = 5145 A. This bleaching appears to be permanent and is shown to present a severe limitation to the operation of nonflowing continuously excited dye lasers. The rate of bleaching has been measured under a variety of conditions and is found to vary linearly with pump power, independent of geometry.
80 citations
01 Apr 1971
TL;DR: In this paper, a discussion of the basic properties of transversely excited CO 2 Lasers is followed by the description of different techniques that have been used to provide effective transverse excitation of lasers at low repetition rates.
Abstract: The development of transversely excited atmospheric pressure (TEA) CO 2 Lasers has led to the generation of multimegawatt laser pulses at 10.6 µm in simple laboratory prototypes. A discussion of the basic properties of these lasers is followed by the description of a number of different techniques that have been used to provide effective transverse excitation of lasers at low repetition rates. The basic technique used to increase the repetition rates to 1000 pulses per second (PPS) is described. Considering the simplicity of the technique and its low cost, it appears that in the not too distant future, pulse energies in the kilojoule region and pulse lengths of the order of one nanosecond will be practical.
72 citations
TL;DR: In this paper, a four-state kinetic model was used to interpret infrared saturations double resonance, and pulse transmission of a CO 2 laser by saturable absorbers, and good agreement was found between the predictions of this model and experimental dependence of such variables as pulsewidth, repetition frequency, and peak power on the presence of buffer gases mixed in with the absorber.
Abstract: Passive Q switching of a CO 2 laser by saturable absorbers is analyzed in terms of a four-state kinetic model previously used to interpret infrared saturations double resonance, and pulse transmission. Good agreement is found between the predictions of this model and the experimental dependence of such variables as pulsewidth, repetition frequency, and peak power on the presence of buffer gases mixed in with the absorber.
56 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
01 Apr 1971
TL;DR: A review of laser-triggered switching (LTS) is given in this article, where the theory of the laser-induced voltage breakdown of as gas-filled spark gap is considered and the theory is compared with observations wherever possible.
Abstract: A review of laser-triggered switching (LTS) is given. The theory of the laser-induced voltage breakdown of as gas-filled spark gap is considered and the theory is compared with observations wherever possible. Included in the review are: voltages ranging from a few kilovolts to more than 3 MV; dielectric media of vacuum, gas, liquid, and solid; delay as low as 1 ns and jitter as low as 0.1 ns.
44 citations
TL;DR: In this paper, the authors described various configurations for the successful operation of a continuous, tunable dye laser and obtained output powers as high as 100 milliwatts using a 1.5 watt argon ion laser at 5145 A as the optical pump for the dye laser, with a tuning range from 5640 A to 6150 A.
41 citations
TL;DR: In this article, an improved technique for using a Littrow-mounted diffraction grating to control the spectral characteristics of tunable lasers is reported, which employs a mirror of intermediate reflectivity between the active medium and the grating.
39 citations
TL;DR: In this article, the outputs of a ruby laser and a tunable dye laser (pumped by the ruby laser) have been frequency-mixed in a proustite crystal.
37 citations
TL;DR: In this paper, a pulsed, tunable dye laser has been used to measure the fluorescence lifetime of low-pressure ICI vapor, and the first reported observation of optical excitation of ICI fluorescence, Collision-free lifetimes on the order of 100 μsec are obtained, with some variation of lifetime with excitation wavelength.
Patent•
09 Aug 1971
TL;DR: In this article, the phase shift and attenuation of the sample beam by the substance to be determined were measured by a preferred sensing system, which indicated both phase shifts and attenuations.
Abstract: A laser produces a beam of optical radiation. The substance to be determined may be CO2, and in this case the laser is a CO2laser. Alternatively, the laser may be a tunable laser, and the beam is split by a beam splitter into sample and reference beams, the sample beam being relatively modified by said substance. The modified beam and the reference beam are united and the united beam is sensed by a detector. The optical lengths of the paths transversed by the reference and sample beams are exactly the same save the influence of said substance. A preferred sensing system indicates both the phase shift and attenuation of the sample beam by the substance to be determined.
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.
TL;DR: Negative ions photodetachment by continuously tunable laser and ion cyclotron resonance spectrometer was performed by as discussed by the authors, using a continuous tunable LIDAR.
Abstract: Negative ions photodetachment by continuously tunable laser and ion cyclotron resonance spectrometer
01 Apr 1971
TL;DR: In this article, the theory of the molecular hydrogen laser is presented and the operation of the device to generate a fast-rising current pulse which travels down the discharge channel at the velocity of light is described.
Abstract: A unique gas laser system suitable for achieving more than a 100-kW peak power in the vacuum ultraviolet spectral region near 1600 A is described. First, the theory of the molecular hydrogen laser is presented. The novel operation of the device to generate a fast-rising current pulse which travels down the discharge channel at the velocity of light is described. Finally, the experimental verification of lasing and further characteristics of the device are given.
TL;DR: In this article, an approximate formulation of the thermal transient effects in laser rods, such as the temperature distribution in the laser rod and the effect of rod distortion on a collimated light beam passing through the rod, is described.
Abstract: An approximate formulation of the thermal transient effects in laser rods, such as the temperature distribution in the laser rod and the effect of rod distortion on a collimated light beam passing through the rod, is described. Also, a computation is made for a practical case and compared to experimental results.
TL;DR: In this article, the design and operating characteristics of a small-scale transverse flow chemical laser source are presented, which is also useful as a selectively tunable probe for single pass gain measurements in chemical lasers.
Abstract: Laser‐induced vibrational fluorescence experiments have been accomplished with a newly developed cw chemical laser. The design and operating characteristics of this small‐scale transverse flow chemical laser source are presented. The fluorescence measurement technique and apparatus provide several advantages over the use of pulsed chemical lasers for similar measurements. The present laser is also useful as a selectively tunable probe for single pass gain measurements in chemical lasers.
TL;DR: In this paper, the spiking condition of dye lasers is analyzed by means of a small-signal approximation of the rate equations, and an initial spike is observed in the output beam of a flash-lamp-excited rhodamine 6G laser with a shortened cavity.
Abstract: The spiking condition of dye lasers is analyzed by means of a small-signal approximation of the rate equations Dye lasers are generally operated close to the border region between spiking and nonspiking An initial spike is observed in the output beam of a flash-lamp-excited rhodamine 6G laser with a shortened cavity
TL;DR: In this paper, the tunable dye ring-laser using multiple prism arrangements was shown to be superior to those of equivalent linear linear lasers in terms of performance and energy efficiency.
TL;DR: In this paper, mode-control experiments at a 30kW CW power level with an unstable resonator at a high Fresnel number were performed on a gas dynamic laser and the output power was more than half of the maximum multi-mode power.
Abstract: Mode-control experiments at a 30-kW CW power level with an unstable resonator at a high Fresnel number were performed on a gas dynamic laser. Near- and far-field intensity distributions were obtained that are consistent with theoretical values for an approximately twice diffraction-limited beam. Under these conditions, the output power was more than half of the maximum multi-mode power.
TL;DR: In this paper, the design of a new type of atmospheric pressure CO 2 -N 2 -He laser capable of producing 1.2-J infrared light pulses with a peak power of 0.5 MW is described.
Abstract: The design of a new type of atmospheric pressure CO 2 -N 2 -He laser capable of producing 1.2-J infrared light pulses with a peak power of 0.5 MW is described. An investigation of the laser output dependence on gas flow, gas mixture, capacitor voltage, output coupling reflectivity, and electrode spacing was made. It is shown that even greater energies and powers should be possible at higher voltages and larger electrode gaps.
TL;DR: In this paper, a tunable dye laser operating continuously in the range 570 nm to 620 nm was described with a single prism and an intracavity etalon, with a short-term bandwidth of less than 4 × 10-5nm (35 MHz) and a long-term stability of better than 2 × 10 −4nm (180 MHz).
Patent•
27 Apr 1971
TL;DR: In this article, a single-frequency laser with a pair of internal grating reflectors photo-induced in a suitably sensitized transparent material doped with an active medium is presented.
Abstract: There is disclosed a compact, narrow-band single frequency laser employing a pair of internal grating reflectors photo-induced in a suitably sensitized transparent material doped with an active medium. Specifically, a laser is obtained in a photosensitized sample of dye-doped poly(methyl methacrylate). It includes an internal resonator formed by a pair of grating reflectors permanently induced in the sample, in which optical guides can also be induced upon exposure to ultraviolet radiation. The resonated laser frequency is selected from the usual broad dye emission spectrum by choice of the grating spacings. Tunability can be achieved by applying stress to the sample to change the grating spacings and the laser resonator length either simultaneously or independently.
TL;DR: In this article, two new types of mode selectors for single-frequency operation in the Nd:YAG laser have been investigated and the relative advantages of these modes are enumerated and it is shown that the laser output may be taken through the metallic-film reflector etalon without serious loss.
Abstract: Mode filters such as an intracavity tilted Fabry-Perot etalon, or an internal metallic film used to obtain a single-frequency output in the Nd:YAG laser, only work well for relatively short lasers (∼15 cm) and at reduced values of laser gain or output power level. Two new types of mode selectors for such single-frequency operation that largely overcome these difficulties are investigated here. These consist of a double metallic-film etalon in the laser cavity, or alternatively a combination of an intracavity tilted Fabry-Perot etalon and a single metallic-film reflector etalon. Both methods are considered in some detail and some experimental results are given on the single-frequency operation of a Nd:YAG laser with such mode filters. The relative advantages of the new mode selectors are enumerated and it is shown that the laser output may be taken through the metallic-film reflector etalon without serious loss.
TL;DR: In this article, it was shown that the tuning rate is a function of the time after the start of the pumping pulse and the pumping current density, and that the behavior of tuning rates is dependent on whether or not lasing action occurs in the crystal under examination.
Abstract: The wavelength at which the stimulated output from a number of electron-beam-pumped semiconductor lasers peaks is a function of the time after the start of the pumping pulse. In general, the output intensity reaches a maximum at short wavelengths considerably before it peaks at the longest. Detailed observations of the wavelength shifts of the peak output as a function of both time and pumping current are reported here for both CdSe and GaAs laser crystals. It is found that the rate of shifting of the wavelength peak (tuning rate) as a function of electron-beam pumping current is very similar in both functional form and magnitude in the two materials. Furthermore, the behavior of the tuning rate is dependent on whether or not lasing action occurs in the crystal under examination. For a crystal in which lasing action is obtained, the tuning rate saturates for pumping current densities above threshold. In contrast, for a nonlasing crystal, the tuning rate is a linearly increasing function of the pumping current density. The implications of these results are discussed with reference to previously reported work concerning shifts with respect to the band edge of the stimulated emission from semiconductor lasers.
TL;DR: Simultaneous Stokes and anti-Stokes electronic Raman scattering has been obtained between the resonance doublets of potassium and rubidium atoms selectively excited by a frequency tunable dye laser as mentioned in this paper.
Abstract: Simultaneous Stokes and anti-Stokes electronic Raman scattering has been obtained between the resonance doublets of potassium and rubidium atoms selectively excited by a frequency tunable dye laser. New Raman scattering components near the resonance lines have been observed with rubidium in the presence of helium.
TL;DR: The average output power of pulsed HF chemical lasers was found to depend strongly on the fluorine source used as mentioned in this paper, and the best performance was obtained from H 2 -C 2 F 6 -He mixes, which gave average powers of 850 mW and energies of 20 mJ/pulse.
Abstract: The average output power of pulsed HF chemical lasers is found to depend strongly on the fluorine source used. The best performance was obtained from H 2 -C 2 F 6 -He mixes, which gave average powers of 850 mW and energies of 20 mJ/pulse. Peak gains of at least 0.036 cm-1are observed. Average powers of 450 mW from DF and 70 mW from HCl are reported.