共查询到20条相似文献,搜索用时 250 毫秒
1.
C. Dréze A. Waksberg B. W. Davis 《International Journal of Infrared and Millimeter Waves》1985,6(5):387-403
A detailed theoretical and experimental study of the heterodyne performance of a quasioptical Schottky diode detector is presented. The experimental results have been obtained by mixing the radiation from a FIR laser with the output of a 67–73 GHz Klystron. The heterodyne signal variation versus various parameters and its relation to the special case of two lasers mixing are described. The mixer characteristics are a NEP value of 2×10–19W/Hz and a detector bandwidth of at least 9 GHz. Experimental evidence of harmonics generation of submillimetric frequencies at the diode junction is also presented. 相似文献
2.
F. He M. Gong L. Huang Q. Liu Q. Wang X. Yan 《Applied physics. B, Lasers and optics》2007,86(3):447-450
A compact diode-side-pumped Nd:GdVO4 laser system using a folded cavity and grazing-incidence configuration is presented. The highest multimode output power obtained
was 21.8 W at 36 W of effective diode pump power. Highest optical-to-optical conversion efficiency of 61.5% was achieved at
33 W of effective diode pump power with 20.3 W of multimode output power. For single-mode TEM00 operation, an intracavity telescope was adopted for mode matching in the horizontal direction. Because of the folded cavity
and the intracavity telescope, this laser head was the most compact to our knowledge of the TEM00 grazing-incidence laser geometry. At last, an output power of 15 W was produced at 36 W of effective diode pump power. The
stable Q-switching operation was also obtained.
PACS 42.55.-f; 42.55.Xi; 42.60.Gd 相似文献
3.
Marek Dobosz Hirokazu Matsumoto Katuo Seta Shigeo Iwasaki 《Optics and Lasers in Engineering》1996,24(1):43-56
Superposition of different-wavelength, multimode- and single-mode laser diode beams is investigated to locate the fringe of zero interference order in a Twyman-Green interferometer. The possibility of central fringe detection using three multimode laser diodes or one single-mode together with a pair of multimode laser diodes is shown. If a single-mode laser diode is applied, a simultaneous fringe-counting technique for displacement measurement is available. The influence of the angle between wavefronts entering the interferometer is analyzed. A repeatability of about 5 nm is shown for surface position determination when using three-beam source. 相似文献
4.
Doubly resonant continuous-wave optical parametric oscillator pumped by a single-mode diode laser 总被引:1,自引:0,他引:1
The performance characteristics of a doubly (signal and idler) resonant continuous-wave optical parametric oscillator based on periodically poled lithium niobate and pumped by a 100-mW single-mode laser diode at 810 nm are reported. Pump power thresholds as low as 16 mW and wavelength tuning over the range 1.15-1.25 microm at the signal and 2.31-2.66 microm at the idler were achieved through variation of crystal temperature, pump wavelength, and grating period. Up to 5 mW of signal output was obtained with the single-mode diode pump, and signal powers of up to 39 mW were obtained when pumping with a 400-mW injection-locked broad-area diode laser. 相似文献
5.
Barbieri S Alton J Beere HE Linfield EH Ritchie DA Withington S Scalari G Ajili L Faist J 《Optics letters》2004,29(14):1632-1634
We demonstrate heterodyne mixing of two free-running, multimode, 3.3-THz quantum cascade lasers by use of a point-contact Schottky diode. By temperature tuning the emission wavelength of one laser, a difference frequency signal spanning the 2-4-GHz range is obtained, with a signal-to-noise ratio of 30 dB. The frequency of the heterodyne signal is subject to random fluctuations of a few megahertz, principally from instabilities in the temperatures of the devices. From single-shot measurements we derive an instantaneous linewidth for a single Fabry-Perot mode of 20 kHz, corresponding to an integration time of 3.6 ms. 相似文献
6.
The lasing condition and frequency stability of the single longitudinal mode oscillation of a diode laser pumped 2 μm Tm,Ho:YLF microchip laser at room temperature are reported. It is shown that the microchip laser with an output mirror of 99.0% reflectivity had better single longitudinal mode performance than that with an output mirror of 99.5% reflectivity. The frequency tuning rate when varying the crystal temperature was estimated to be 1.9 GHz/°C. Frequency stability of the microchip laser is examined by the self-beating heterodyne detection method for several delay times between 0.48 and 4.8 μs. It is indicated that the spectral fluctuation is in proportion to the delay time and the increasing rate is 2.3 kHz/μs. 相似文献
7.
基于多模光纤滤波器的可调谐掺铒光纤激光器 总被引:1,自引:0,他引:1
研究了一种新型、全光纤、宽带可调谐环形腔掺铒光纤激光器。该激光器利用由单模-多模-单模光纤组成的滤波器实现波长可调谐及激光器的全光纤结构。该滤波器将多模光纤缠绕在偏振控制器上,两端分别与一段单模光纤相连,通过调整偏振控制器的状态,实现了中心波长1542~1560nm的不同激光输出。单波长连续可调谐激光器的波长可调范围为18nm,边模抑制比大于40dB,3dB线宽为0.096nm;进一步调整偏振控制器的状态和抽运功率,实验同时得到了连续可调谐的双波长、三波长等多波长激光输出。对于可调谐的多波长激光器,通过调整偏振控制器的状态,可实现波长间隔及输出中心波长两者可调。 相似文献
8.
The theory of phase-drift-suppression method and simulated results using sinusoidal and triangular phase modulation have been described. The computed signal intensity is defined as the square root of the sum of squares of each harmonic intensity in the heterodyne beat signal. The relations between the computed signal intensity, its relative standard deviation, and the modulation indexes are shown through simulations. Modulation indexes that suppress the phase drifts were obtained, including up to the eighth harmonic. The stability of the beat signal in sinusoidal and triangular phase modulation was confirmed to increase 245 times using harmonics from the fundamental to the fourth order and a modulation index of 2.8 rad, and to increase 490 times using harmonics from the fundamental to the second order and 2.9 rad. 相似文献
9.
Optical feedback from a high-finesse V-resonator, developed for this study, results in efficient coupling with an extended
cavity diode laser, stabilizing its emission frequency and strongly decreasing the laser linewidth. This in turn enhances
resonator output power, thus increasing the signal-to-noise ratio when used for the detection of gas phase species by absorption
spectroscopy. This effect was directly measured by heterodyning two extended cavity diode lasers at a wavelength of 409 nm
with and without the influence of optical feedback from a high-finesse V-resonator. The heterodyne signal of freely running
lasers is composed of a set of sharp peaks whose envelope shows a width on the order of 4.5 MHz at a sweep rate of 80 MHz/0.8 s,
leading to a laser linewidth of 3 MHz. Optical feedback from the high-finesse V-resonator reduces the heterodyne signal to
a single peak with a mean width of 10 kHz, leading to a laser linewidth of 7 kHz. This is the lowest value of linewidth, reported
thus far, for diode lasers operating in this wavelength region. 相似文献
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12.
We are particularly interested in the measurement of nonlinear acoustic waves in air, within the range of the Raman-Nath diffraction regime. We used a heterodyne laser interferometric system with a Bragg cell frequency of 80 MHz. A harmonic power acoustic wave with a frequency in the range of 20 kHz was generated, but higher harmonics appear when nonlinear propagation occurs in restricted volumes or waveguides. This topic raises a number of interesting questions. The most complex problem arises when processing an extremely wide-band output signal from a photo-detector, where the signal contains a huge number of high amplitude harmonics in a measured acoustic signal. The wide-band output signal from nonlinear wave measurement was simulated by means of similar wide-band output signals obtained by measuring known dynamic mechanical displacements. Because the frequency band of common analog circuits used for signal processing is too narrow, the output signal from the interferometer was digitalized and processed. This paper discusses the results of these tests and provides estimates of the frequency restrictions of signal processing. 相似文献
13.
In this paper, based on a system composed of a multimode emitted laser diode and a single-mode received laser, chaos synchronization performance has been investigated numerically under different optical injection patterns. The results show that, for single mode injection (SMI) which means the received laser is injected by a selective longitudinal mode of the multimode emitted laser whose wavelength corresponds to that of the single-mode received laser, the system synchronization performance is better than that with multi mode injection (MMI); depending on the optical spectrum of the received laser, the physical mechanism of chaos synchronization deterioration for MMI is given. Additionally, after taking into account the parameter mismatches, the chaos synchronization performance of the system with different injection pattern have also been discussed. For either SMI or MMI, the synchronization performance with negative parameter mismatches is better than that with positive parameter mismatches. 相似文献
14.
A sweep optical frequency synthesizer is demonstrated by using a frequency-stabilized optical frequency comb and injection-locked distributed-Bragg-reflector (DBR) laser diode. The injection-locked DBR laser acts as a single-frequency filter and, simultaneously, a high-gain amplifier of the optical frequency comb. The frequency instability of the heterodyne beat signal between two independently injection-locked DBR lasers is measured to be 2.3 x 10(-16) at 1 s averaging time. The output frequency of the sweep optical frequency synthesizer can be precisely tuned over 1 GHz, and a saturated absorption spectrum of the Cs D2 line at 852 nm is recorded by the injected DBR laser. 相似文献
15.
High-energy single-transverse-mode Q-switched fiber laser based on a multimode large-mode-area erbium-doped fiber 总被引:5,自引:0,他引:5
Offerhaus HL Broderick NG Richardson DJ Sammut R Caplen J Dong L 《Optics letters》1998,23(21):1683-1685
We demonstrate that appropriately designed doped multimode fibers provide robust single-mode output when used within a fiber laser cavity. Using a novel large-mode-area fiber, we demonstrate what we believe to be record single-mode (M(2) <1.2) pulse energies of >0.5 mJ from a Q -switched fiber laser and even higher pulse energies (as high as 0.85 mJ) with slightly compromised spatial-mode quality (M(2)<2.0) . This approach offers significant scope for extending the range of single-mode output powers and energies that are achievable from fiber-laser-amplifier systems. 相似文献
16.
《中国光学快报(英文版)》2016,(7)
Based on the modified ramp and fire technique, a novel injection seeding approach with real-time resonance tracking is successfully demonstrated in a single-frequency Nd:YAG pulsed laser. Appling a high-frequency sinusoidal modulation voltage to one piezo actuator and an adjustable DC voltage to another piezo actuator for active feedback, single-mode laser output with high-frequency stability is obtained, and the effect of the piezo hysteresis on the frequency stability can be eliminated for a laser diode pumped Q-switched Nd:YAG laser at a repetition rate of 400 Hz. 相似文献
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18.
G.W. Baxter M.A. Payne B.D.W. Austin C.A. Halloway J.G. Haub Y. He A.P. Milce J.F. Nibler B.J. Orr 《Applied physics. B, Lasers and optics》2000,71(5):651-663
Optical parametric oscillator (OPO) and amplifier (OPA) devices are useful for spectroscopic sensing of chemical processes
in laboratory, industrial, and environmental settings. This is particularly true of nanosecond-pulsed, continuously tunable
OPO/OPA systems, for which we survey a variety of instrumental strategies, together with actual spectroscopic measurements.
The relative merits of OPO wavelength control by intracavity gratings and by injection seeding are considered. A major innovation
comprises an OPO with a ring cavity based on periodically poled lithium niobate (PPLN) and injection-seeded by a single-mode
tunable diode laser (TDL). Active cavity control by an ‘intensity dip’ method yields an optical bandwidth ≤0.005 cm-1 (150 MHz), which compares favourably with the performance of advanced grating-tuned OPO/OPA systems. A novel adaptation of
this TDL-seeded PPLN OPO employs a compact, inexpensive multimode pump laser, with which it is still possible to obtain continuously
tunable single-mode signal output. Cavity ringdown (CRD) spectroscopy also figures prominently, with infrared (IR) CRD spectra
from both grating-scanned and TDL-seeded OPOs reported. Finally, a tunable ultraviolet (UV) source, combining a TDL-seeded
passive-cavity OPO and a sum-frequency generation stage, is developed for measurements of time-resolved IR-UV double resonance
spectra of acetylene and UV laser-induced fluorescence spectra of nitric oxide.
Received: 28 March 2000 / Published online: 13 September 2000 相似文献
19.
We present experimental demonstration of an end-pumping scheme based on splicing the multimode pump and single-mode signal fibers directly to a double-clad fiber with a tailored cross section. The method is used to pump a double-clad, erbium- and ytterbium-doped, fiber ring laser. The efficiency of the end-pumping method is tested by determining the slope efficiencies of the fiber ring laser and the fiber laser in a Fabry-Perot configuration. Comparable slope efficiencies are found when both laser configurations have similar output coupler ratios. The developed pumping scheme and double-clad fiber can find applications in cost-effective power fiber amplifiers and lasers. 相似文献