Gregory J. Wagner

Continuous-wave broadly tunable Cr2+:ZnSe laser.

We report room-temperature operation of an all-solid-state broadly tunable continuous-wave Cr(2+):ZnSe laser. Output power of 250 mW, an absorbed power slope efficiency of 63%, and continuous tunability from 2138 to 2760 nm are demonstrated.

Mode-locked Cr 2+ :ZnSe laser

We describe active mode locking of a Cr(2+):ZnSe laser operating near 2.5 mum. The laser produces 4.4-ps transform-limited Gaussian-shaped pulses and produces 82 mW of average power.

Tunable infrared laser sources for DIAL

Broadly tunable infrared laser sources are of interest for a variety of applications including differential absorption lidar, differential scattering lidar, multi-spectral detection and imaging, hard target identification and discrimination, optical communications in poor visibility conditions, and spectroscopy. For chemical sensing applications, sources are particularly sought in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions. A variety of laser and nonlinear optical devices have been demonstrated that access these wavelengths. In particular, CTI is developing novel, tunable, narrow linewidth transmitters for coherent and direct detection lidar measurement applications. An example is a multi-watt Cr:ZnSe laser that is tunable over the 2.1 to 2.8 micrometers wavelength region. This laser has been used to pump-tune optical parametric oscillators (OPOs) that are broadly tunable across the MWIR and LWIR. We are also developing tunable Yb lasers that can be used to pump OPOs that emit signal beams in the eyesafe 1.55 micrometers region while generating idler beams that access the 3 to 4 micrometers MWIR band. This paper describes these sources.

Power scaling of Cr2+:ZnSe lasers

We describe continuous-wave, quasi-continuous-wave and gain-switched operation of moderate power Cr:ZnSe lasers. We have demonstrated CW output powers as high as 1.83 W, quasi-CW power of 3.6 W at 10% duty cycle, and 0.35 mJ gain- switched pulses at a repetition frequency of 1000 Hz.

High power Q-switched Tm:YAlO3 lasers

We have demonstrated 50 W of output power from a free-running Tm:YAlO3 laser at 1940 nm. We have also obtained Q-switched operation with 7 mJ of output energy at a 5 kHz repetition rate.

Chromium-doped chalcogenide lasers

This paper reviews fundamental material properties and the current state-of-the-art of continuous-wave and pulsed Cr/sup 2+/ doped chalcogenide lasers. Multi-watt output powers are demonstrated in both CW and pulsed modes of operation. Laser output and optical-to-optical conversion efficiency for a Cr:ZnSe laser operating at 7 kHz pulse repetition frequency are presented.

Single-Frequency Cr:ZnSe Laser

We have demonstrated single-longitudinal mode operation of a Cr:ZnSe laser at a wavelength of 2460 nm. The laser produced ~10 mW of output and had a linewidth of less than 20 MHz.

High-power, rapidly-tunable dual-band CdSe optical parametric oscillator

We report on a Cr:ZnSe laser pump-tuned, intracavity CdSe optical parametric oscillator (OPO) with signal and idler tunable from 2.8 to 3.7 μm and 8.2 to 8.8 μm respectively and output power of 3 W.

High-brightness, rapidly-tunable Cr:ZnSe lasers

We report a high-brightness, rapidly-tunable Cr:ZnSe master-oscillator power-amplifier producing greater than 5 W of average power with near diffraction limited beam quality and 2 GHz linewidth. An 18.5 W Cr:ZnSe power oscillator was also demonstrated.

Mid-Wave ZGP OPOs Pumped by a Cr:ZnSe Laser

A ZnGeP2 (ZGP) optical parametric oscillator (OPO) is described that is pumped by a gain-switched Cr2+:ZnSe laser and which is broadly pump-tuned in the midinfrared. Both Type I and Type II ZGP OPOs operating in the 4 to 6 µm region are demonstrated with slope efficiencies as high as 53%. The Type II configuration is noncritically phase matched and can potentially tune from 3.4 to 6.1 µm by tuning the pump laser from 2.1 to 2.9 µm. The Type I configuration can either angle- or pump-tune over nearly the entire transparency range of ZGP.