A compact, continuous-wave terahertz source based on a quantum-cascade laser and a miniature cryocooler

Abstract

We report on the development of a compact, easy-to-use terahertz radiation source, which combines a quantum-cascade laser (QCL) operating at 3.1 THz with a compact, low-input-power Stirling cooler. The QCL, which is based on a two-miniband design, has been developed for high output and low electrical pump power. The amount of generated heat complies with the nominal cooling capacity of the Stirling cooler of 7 W at 65 K with 240 W of electrical input power. Special care has been taken to achieve a good thermal coupling between the QCL and the cold finger of the cooler. The whole system weighs less than 15 kg including the cooler and power supplies. The maximum output power is 8 mW at 3.1 THz. With an appropriate optical beam shaping, the emission profile of the laser is fundamental Gaussian. The applicability of the system is demonstrated by imaging and molecular-spectroscopy experiments.

Broadly tunable terahertz generation in mid-infrared quantum cascade lasers

“…4c, inset). In comparison, THz QCLs systems integrated with pulsed-tube cryorefrigerators 26 or Stirling cryocoolers 27 have a wall-plug efficiency of about 10 À 5 , once taking into account the power consumption of the cooling system. Clearly, a cryocooler also adds to the system size and complexity.…”

THz quantum-cascade laser as a local oscillator for SOFIA

“…The whole system weights less than 15 kg including cooler, power supplies etc. [2]. We will present the performance of the lasers in the cryocooler with respect to output power and beam profiles.…”

High-spectral-resolution terahertz imaging with a quantum-cascade laser

“…Details of the active region are described in [14]. The QCL is mounted in a compact Stirling cryocooler (Ricor K535) and operated at a temperature of 40 K [15]. The exit window is made of high-density polyethylene (HDPE).…”