Goal of 10 GHz Mode Locked Mid-IR Microchip Waveguide Lasers
Abstract
Prof Ajoy Karr, Heriott-Watt University, Unite Kingdom in collaboration with researchers at Milano Polytechnic, Italy developed a room temperature Kerr-lensing mode (KLM) locked Chromium and Iron doped Zinc Selenide (Cr:ZnSe) II-VI material laser, which is centered at 2.4 micron wavelengths. The KLM allows self-compression of the pumping diode laser, creating extremely short temporal (< 10-13 seconds high pulse rate, intense laser pulses. It essentially compresses a small amount of laser energy into a very short amount of time to generate militarily useful non-linear effects in the target at low overall low system power. This wavelength is important because it represents a higher power transmission window than standard 1 to 1.6 micron wavelength lasers operate in, making the KLM laser highly useful for Infrared Counter Measures (IRCM). The ZnSe was doped using Hot Isostatic Pressing (HIP) treatment also developed and optimized under a previous EOARD Grant and transitioned to AFRL/RYD. The laser operates with a pulse repetition frequency (PRF) of 182 MHz demonstrating at an average output power of 140 milli-Watts. The KLM laser output power was simply limited due to the lack of funding to create a thermal management system to enable increased power. The most valuable outcome of the research however was that he achieved ultra-short pulsed laser (USPL) durations, down to 37 femto-seconds (fs), by exploiting intra-cavity chirped mirrors for dispersion control. To achieve these short pulse durations, a world-record for ZnSe, typically requires a very large series of stretching and compressing diffraction gratings and optics, however the Cr:ZnSe KLM laser achieved this in a space of < 30 cm x 30 cm x 8 cm with an X-fold laser geometry.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 04, 2021
- Accession Number
- AD1154574
Entities
People
- Ajoy Kar
Organizations
- Heriot-Watt University