Distributed-feedback Quantum Cascade Laser Operating Research Articles

High-temperature continuous-wave operation of low power consumption single-mode distributed-feedback quantum-cascade lasers at λ∼5.2 μm

Continuous-wave operation of a distributed-feedback quantum-cascade laser in a packaged module is demonstrated up to a heat sink temperature of 80 °C with an output power of greater than 10 mW and a power consumption of less than 3.8 W. Single longitudinal mode emission near 5.24 μm is observed over a temperature range from 10 to 80 °C with a side mode suppression ratio greater than 20 dB limited by the instrumentation. A single spatial mode is determined with far-field pattern measurement. The above performance is achieved using a buried heterostructure and a small cavity of 7.6 μm×1.5 mm.

Quantum Cascade Laser-Based Photoacoustic Sensor for Trace Detection of Formaldehyde Gas

We report on the development of a photoacoustic sensor for the detection of formaldehyde (CH2O) using a thermoelectrically cooled distributed-feedback quantum cascade laser operating in pulsed mode at 5.6 μm. A resonant photoacoustic cell, equipped with four electret microphones, is excited in its first longitudinal mode at 1,380 Hz. The absorption line at 1,778.9 cm−1 is selected for CH2O detection. A detection limit of 150 parts per billion in volume in nitrogen is achieved using a 10 seconds time constant and 4 mW laser power. Measurements in ambient air will require water vapour filters.

High-power, continuous-wave operation of distributed-feedback quantum-cascade lasers at λ∼7.8μm

The authors present high-power continuous-wave (cw) operation of distributed-feedback quantum-cascade lasers. Continuous-wave output powers of 56mW at 25°C and 15mW at 40°C are obtained. Single-mode emission near 7.8μm with a side-mode suppression ratio of ⩾30dB and a tuning range of 2.83cm−1 was obtained between 15 and 40°C. The device exhibits no beam steering with a full width at half maximum of 27.4° at 25°C in cw mode.

Room-temperature, high-power, and continuous-wave operation of distributed-feedback quantum-cascade lasers at λ∼9.6μm

High-power continuous-wave (cw) operation of distributed-feedback quantum-cascade lasers is reported. Continuous-wave output powers of 100mW at 25°C and 20mW at 50°C are obtained. The device exhibits a cw threshold current density of 1.34kA∕cm2, a maximum cw wall-plug efficiency of 1% at 25°C, and a characteristic temperature of ∼190K in pulsed mode. Single-mode emission near 9.6μm with a side-mode suppression ratio of ⩾30dB and a tuning range of 2.89cm−1 from 15to50°C is obtained.

High-power, room-temperature, and continuous-wave operation of distributed-feedback quantum-cascade lasers at λ∼4.8μm

A high-power continuous-wave (CW) operation of distributed-feedback quantum-cascade lasers using a buried grating with epitaxial regrowth up to temperatures of above 60°C is demonstrated. For a high-reflectivity-coated 13μm-wide and 3mm-long cavity, CW output powers of 135mW at 25°C and still 37mW at 60°C are obtained. The device exhibits a CW threshold current density of 1.1kA∕cm2, a maximum CW wall-plug efficiency of 1.48% at 25°C, and a characteristic temperature of 177K in pulsed mode. Single-mode emission near 4.8μm with a side-mode suppression ratio of >30dB and a tuning range of ∼8.1cm−1 (i.e., tunability of 0.18cm−1∕K) in the temperature range from 15to60°C is observed.