Recent Advances in IR Laser Diodes with High Power, High WPE, Single Mode, CW Operation at RT

Abstract

Quantum cascade lasers (QCLs) are important practical sources for infrared spectroscopy. Recent research in mid-IR QCLs has resulted in record high wallplug efficiency, output power, single mode operation and wide tunability. The spectroscopic range of QCL has been extended to as short as 3 μm, opening up possibility of detection of a wide range of molecules. Wide tuning based on dual section sampled grating distributed feedback QCLs has resulted in individual tuning of 50 cm−1 and 24 dB side mode suppression ratio with continuous wave operation greater than 100 mW. Need for compact, room temperature sources, in spectral range constituting the THz gap, has led to QCL based THz sources by difference frequency generation with modal or Cherenkov phase matching schemes. Single mode emission from 1 to 4.6 THz with side mode suppression ratio up to 40 dB and THz power of 65 μW at 4 THz are demonstrated.