Broadband and rapid tuning of an all-solid-state single-frequency Nd:YVO4 laser

A diode-pumped tunable single-frequency Nd:YVO₄ laser has been built. The laser incorporates a LiNbO₃ etalon (LE) as a coarse tuning element and a LiNbO₃ crystal (LC) as a fine tuning element to obtain broadband, rapid tuning. More than 480 mW of output power has been obtained from the tunable laser with frequency tuning range of 17.2 GHz and the tuning response time of 10 ns. PACS 42.55.Xi; 42.60.Da; 42.60.Fc; 42.60.Pk     

Fast mode-hop-free acousto-optically tuned laser with a simple laser diode

A mode-hop-free tunable external-cavity Littrow diode laser with intracavity acousto-optic modulators (AOMs) has been built. The modes of the red laser diode without a special antireflection coating are shifted by varying the injection current. The external resonator modes and the grating selectivity are independently electrically alterable by two AOMs. Thus, a tuning of the external resonator over up to 1900 GHz is possible. A precise computer control of laser diode and AOMs allowed a single-mode tuning of the whole laser with a tuning range of 225 GHz in 250 s. Additionally, we demonstrated fast tuning over 90 GHz in 190 micros and a repetition rate of 2.5 kHz.     

Diode laser action in Pb1-xMnxS

Diode laser action has been observed in Pb_1-xMn_xS alloy system for molar fraction of MnS x = 0.014 at the emission energy of 320 meV at 15 K. Combined current and magnetic field tuning has been examined in the range of 2.4–9.0 A and 0–14 kG, respectively and a quasi continuous tuning in the energy range from 320.5 meV to 322.0 meV was achieved. This is a first report about laser action in semiconductors containing paramagnetic ions.     

Research on tunable local laser used in ground-to-satellite coherent laser communication

In order to realize homodyne reception and Doppler frequency shift tracking in ground-to-satellite coherent laser communication, a local laser is experimentally demonstrated in this Letter. It is realized based on modulationsideband injection locking, and has a 10 GHz tuning range, a 1 THz/s tuning rate, a 5 k Hz linewidth, and 16 m W of output power. When applied to a Costas loop in a coherent laser communication system, the local laser can achieve ?5 GHz Doppler frequency shift tracking with a 20 MHz/s frequency shift rate, which is sufficient for the ground-to-satellite coherent laser communication.     

Widely tunable Yb-doped laser with all fiber structure

In this paper, an all fiber Yb³⁺-doped fiber ring laser with large tuning range has been reported. A 976 nm laser diode (LD) pumped laser is used as the pump source and high concentration Yb³⁺-doped fiber is adopted as gain medium. Adjusting the polarization controller (PC), a widely tunable range of 20 nm from 1030 to 1050 nm is obtained. The spectral linewidth of the pulse is less than 0.2 nm. Comparing with other fiber laser structures, the fiber laser with an all-fiber structure has higher efficiency and better stability. The laser also has very stable and flat output within the whole tuning range.     

Rapid wavelength scanning based on acousto-optically tuned external-cavity laser diode

High-speed, wide-range wavelength scanning is demonstrated using a laser diode with an antireflection coating and an external cavity employing an acousto-optic deflector. The narrow spectral width of 0.2 nm observed in the experiment indicates the availability of a highly coherent laser beam. The scanning range of 15 nm under rapid modulation is confirmed in the prototype system. A tuning rate of more than 100 kHz is achieved without any mode hops. To the best of our knowledge, no such high-speed wavelength tuning based on an acousto-optical configuration has been demonstrated thus far.     

Full-automatic broad-band wavelength control of a pulsed dye laser

A full-automatic wavelength controled pulsed dye laser has been developed. With the control system, dye laser oscillations of nanosecond pulses are tuned to any wavelength in the visible or scanned in any sweep mode keeping the nearly transform-limited bandwidth of 0.45 GHz. A mechanical tuning of the wavelength is employed, such that the motion of three wavelength selectors is synchronized to give a smooth and precise wavelength control. The basic principle underlying the tuning scheme, various requirements to be met in system construction, and the practical performance of automatic wavelength control are described in this paper.     

微片Ｎｄ∶ＹＡＧ 双频激光器腔调谐现象研究

 基于微片Ｎｄ∶ＹＡＧ 正交偏振双频激光器,研究了若干重要的双频激光器腔调谐现象, 包括光强调谐、频差调谐、子谐振腔效应及频差闭锁等,给出了实验结果和数据。腔调谐下,正交双频的频差调谐量约为３５０ ｋＨｚ;存在子谐振腔效应时,频差调谐量最大可达到２ ＭＨｚ;未发现明显频差闭锁现象,频差最小值可达到１４ ＭＨｚ。     

A frequency doubled dye laser with a servo-tuned crystal

Spectral tuning of the uv output of a frequency doubled dye laser has been successfully controlled by a servo motor system which tilts the nonlinear crystal appropriate for phase-matched second harmonic generation while the dye laser emission wavelength is tuned. The spatial direction of the generated uv beam is used as the regulating signal. The feasibility of this technique for spectroscopic applications has been successfully tested.     

Tunable laser thin film interrogation

Film thickness is not only a crucial parameter in producing processes, such as semiconductor and optics production, but also a monitored variable in chemistry and biology, for example for tissue microscopy. Many working principles have been demonstrated and are in use in different fields due to their different limitations (observation film thickness, accuracy, measurement speed, etc.). One of these working principles is thin film reflectometry (TFR). One method is based on a laser source and monitors the reflected intensity over growing film time. Another one employs a spectrally broad light source and measures the reflected intensity using a spectrometer. We introduce and demonstrate a measurement system based on a tunable laser stage. There are several different setups for laser wavelength tuning. One of the most promising solutions is based on monolithic laser diodes. Rapid tuning of the lasers wavelength is crucial for achieving high measurement rates. Monolithic laser diodes offer highest tuning rates and hence high performance. On the other hand, mechanically tunable lasers show broadband spectra that result in higher thickness accuracy in this particular application. Hence, we show a comparison of thin film measurements with a monolithic and a mechanically tunable laser source. This comparison shows that the measurement accuracy of the monolithic laser diode can compete with mechanical tuning. Furthermore, it is a promising approach when measurement tuning speed is an issue.     

An efficient S-band brillouin erbium fiber laser with additional EDFA

A short wavelength band brillouin–erbium fiber laser (S-band BEFL) with enhanced characteristics is demonstrated using an additional erbium-doped fiber amplifier (EDFA) in the sub-loop of the laser system. Compared with the conventional BEFL without the additional EDFA, the enhanced BEFL has improved the number of channels as well as the flatness of the brillouin Stoke's peak power. By incorporating a double-pass EDFA, a stable output laser comb up to 8 channels was obtained at 1503 nm wavelength region with peak power variation for the first three Stokes is reduced from 30.9 to 5.4 dB. The incorporation of additional EDFA also increases the tuning range of the BEFL, which the maximum tuning range of 1.8 nm was obtained with the single-pass scheme. The S-band BEFL has constant spacing of 0.09 nm or 11 GHz, which has a potential application in dense wavelength division multiplexed system.     

A 1 MWP-terphenyl dye laser

P-terphenyl in cyclohexane, has been pumped by a KrF laser in a longitudinal configuration. Dye laser pulses of 11 mJ, 1 MW were obtained with over 10% conversion efficiency. N₂ purge of the dye solution is shown to increase the conversion efficiency. The tuning curve between 321.8 nm and 365.3 nm is presented.     

Widely tunable compact erbium-doped fiber ring laser for fiber-optic sensing applications

A compact erbium-doped ring-shaped fiber laser suitable for fiber-optic sensing applications has been developed. The fiber laser utilized a tunable fiber Fabry–Perot filter as the tuning element and had a moderate milli-Watt level power output over almost the whole tuning range from 1530 to 1595 nm with a power fluctuation of 0.15 dB. High repetition rate scanning of laser operation over the whole tuning range was achieved at rates of up to 200 Hz. Moreover, the performance of the ring-shaped fiber laser configured with a high-concentration erbium-doped fiber was investigated for its larger wavelength tunability of over 100 nm. Output power characteristics of this ring-shaped fiber laser were also investigated when it worked in a scanning mode. A distorted power wavelength dependence, as well as some pulsing phenomenon were observed in scanning mode.     

A grating tuned cw dye laser

We report on the operation of a rhodamine 6G cw dye laser involving a simple tuning mechanism capable of achieving high output powers (～500 mW) and resolving power (0.004 nm) close to the Doppler limit for a range of light gases. The system employs a 600 line/mm diffraction grating external to, but coupled with a high Q laser cavity; continuous tuning over 50 nm of the fluorescence spectrum of the dye was obtained.     

基于重采样技术的调频连续波激光绝对测距高精度及快速测量方法研究

调频连续波激光测距方法可以实现高精度的大尺寸绝对距离测量, 且测量过程无需合作目标, 在大空间坐标精密测量领域有很高的研究价值. 而如何提高测量分辨率和实用化一直是近年来调频连续波激光绝对测距研究的热点. 本文研究了调频连续波激光测距的原理, 基于双光路调频连续波激光测距系统, 提出了通过信号拼接提高测量分辨率的信号处理优化方案, 该方案可以提高测距分辨率, 且可以降低对激光器的性能要求; 提出了可实现高速测量的简易测量方法. 设计加工了双光路光纤调频连续波激光测距系统, 利用该系统进行了测距分辨率及测距误差标定实验, 实验结果表明: 优化方案可以有效地提高测量分辨率和测量效率, 在26 m测量范围内, 测距分辨率达到了50 μm, 测距误差不超过100 μm; 快速测量方案有较高实用价值.     

溴化亚铜激光泵浦的可调谐微微秒染料激光

本文首次报道了利用脉宽为25ns重复率为10kHz的溴化亚铜激光泵浦混有饱和吸收体DODCI的超短腔染料激光,产生出30ps光脉冲.在理论上对混入DODCI的超短腔染料激光脉冲压缩效应作了分析计算,计算结果与实验基本一致.在实验上又通过一个放大-色散系统实现对此染料激光脉冲的同步放大和调谐,并达到傅里叶变换极限.     

Grating feedback in a 810 nm broad-area diode laser

Narrow linewidth, single spectral mode operation has been obtained in a high power, 810 nm broad-area diode laser in an extended cavity configuration with a grating as external reflector (grating feedback). For stable operation it was necessary to misalign the feedback slightly in the plane of the laser junction. Characteristics of the thus obtained laser system are a linewidth below 5 MHz, an output intensity of about 50% of the free running power, a large-scale tuning range of 15 nm and continuous scanning over 4 GHz. In the spatial domain, the laser remains multimode and astigmatic. To show the practical applicability of this system, saturated absorption of a krypton line is demonstrated.     

Tunable dye laser configurations

Various configurations for the successful operation of a continuous, tunable dye laser are described. Output powers as high as 100 milliwatts have been obtained using a 1.5 watt argon ion laser at 5145 Å as the optical pump for the dye laser, with a tuning range of from 5640 Å to 6150 Å.     

Linearised tuning of a cw spin-flip Raman laser using anti-reflection coated cavities

By reducing the electron concentration of the InSb cavity and anti-reflection coating its ends, the frequency tuning of a cw spin-flip Raman laser has been linearised to ?99% of the spontaneous tuning rate, and the magnitude of mode jumps decreased to ? 30 MHz (0.001 cm^-1).     

基于LabVIEW的He-Ne激光器综合实验系统

基于LabVIEW软件和数据采集卡设计了激光器综合实验系统,可实现对激光器谐振腔长调谐的自动、远程、精密的控制,并具有对输出光强信号进行实时显示、存储、读取和处理的功能,同时将频率分裂、模竞争和光强调谐实验相结合.