室温大能量宽调谐Fe:CdTe中红外激光技术研究

5-7μm中红外激光在分子光谱学、呼出气体医学诊断和爆炸物稽查等领域有重要应用前景。长期以来，该波段激光的产生技术严重匮乏。Fe:CdTe晶体具有优良的物理特性和光谱特性，是实现大能量、宽调谐中红外激光输出最有前途的材料之一。由于Fe2+离子上能级寿命随温度升高迅速下降，室温Fe:CdTe激光器只能通过窄脉冲光源泵浦才能获得高效输出。受2.94μm窄脉冲激光泵浦源能量的限制，目前此类激光最高输出能量仅为2-3mJ。本项目以3.8μm非链式高能窄脉冲DF激光器泵浦Fe:CdTe晶体，通过有效抑制横向寄生振荡，获得高效激光输出。采用小角度双向对称泵浦方案和光栅谐振腔，可将室温Fe:CdTe激光脉冲能量提高数十倍，在室温条件下获得脉冲能量>100mJ、波长调谐范围>1μm的Fe:CdTe中红外激光输出。通过解决相关机理与技术问题，探索实现大能量、宽调谐室温中红外激光输出的新途径。

The mid-IR laser sources operating in the 5-7μm wavelength region are in great demand for a variety of applications including molecular spectroscopy, Breath analysis for non-invasive medical diagnostics, stand-off detection of explosion hazards. There is a lack of robust solid-state mid-IR laser sources with widely tunable output in this waveband. Fe:CdTe crystal offers a unique blend of physical (high thermal conductivity, low saturation intensity), spectroscopic characteristics(ultrabroad gain bandwidth, high absorption coefficient) that make it the gain media of choice for effective tunable lasing in the mid-IR region. Problem with this active material arises from the fact that the upper laser level lifetime of Fe2+ ions in CdTe sharply shortens with elevated temperature. To achieve satisfactory efficiencies at room temperature, it is necessary to excite the crystal by short pulses. The energy of Fe:CdTe laser in this case was only 2-3mJ, limited by the low energies of 2.94μm Q-switched solid-state lasers used for pumping. .In this project, the characteristics of Fe:CdTe laser in a scheme with two sides small angle pumping by a nonchain discharge pulsed high energy DF laser will be studied. Transversal parasitic oscillation must be suppressed for efficient lasing. The aim of the project is obtaining room temperature Fe:CdTe laser with output energy E>100mJ, widely tunable over the whole spectral range of 5.1-6.3μm with grating resonator. By solving the mechanical problems and key technologies, a novel routine for realizing room temperature high energy widely tunable Fe:CdTe laser will be explored.