Takahide Ochiai

Room temperature, continuous-wave operation of quantum cascade lasers with single phonon resonance-continuum depopulation structures grown by metal organic vapor-phase epitaxy

We propose a new quantum-cascade laser structure with single phonon resonance-continuum depopulation and demonstrate room temperature, continuous-wave operation of the proposed 7.9μm quantum-cascade laser. The laser grown by metal organic vapor-phase epitaxy emits a cw output power of 36mW at 30°C, exhibiting a threshold current density of 2.23kA∕cm2. The cw operation is reported for higher temperatures up to slightly above 60°C. The proposed structure may lead to a successful commercial mass production of the lasers.

High-performance quantum cascade lasers with wide electroluminescence (∼600 cm−1), operating in continuous-wave above 100 °C

The authors report high temperature continuous-wave (cw) operations of broad-gain quantum cascade lasers based on the anticrossed dual-upper-state to multiple-lower-state design. The devices exhibit extremely wide electroluminescence (>600 cm−1) and subthreshold amplified spontaneous emission (∼570 cm−1) spectra at room temperature. Despite showing such broad electroluminescence spectra, the high-reflection coated, buried heterostructure lasers operating at 6.8 μm demonstrate a low threshold current density of ∼1.5 kA/cm2 and a high power of >500 mW with a high slope efficiency of ∼1.6 W/A in cw mode at 300 K. The maximum cw operating temperature of above 100 °C is achieved.

Quantum cascade lasers based on single phonon-continuum depopulation structures

We report a high performance operation of quantum cascade lasers based on Single Phonon-Continuum depopulation (SPC) structures. The lasers exhibit low CW threshold current densities and high characteristic temperatures in the wide wavelength range between 4.5 and 10.8 μm. An 8.2 μm laser, despite a bare ridge structure which is extremely simple configuration without any intentional thermal dissipation equipments and any HR coatings, demonstrates the high device performance: a low threshold current density of 1.66 kA/cm2 and a high maximum output power of 76 mW (from one facet) at room temperature in CW operation. Our shortest wavelength 4.5 μm laser with HR coating reveals a low threshold current density of 1.7 kA/cm2 and maximum output power of 161 mW at room temperature in CW operation. For long wavelength, we present the first room temperature, CW operation of DFB QCL with top grating. The DFB laser emits ~9.6 μm single mode spectra at temperatures between -5 °C and 50 °C. The wide tuning range is obtained to be from 1031 to 1039 cm-1.

Room temperature, CW operation of 5.2 μm quantum cascade lasers with simple ridge structures, grown by MOVPE

We demonstrate room temperature, CW operation of a 5.2 mum quantum-cascade laser with single phonon resonance-continuum depopulation structure, grown by MOVPE. The laser exhibits a simple ridge structure without high reflection coatings.

Room Temperature, Continuous-Wave Operation of Quantum Cascade Lasers with Single Phonon Resonance-Continuum Depopulation Structures

We propose a new quantum-cascade laser structure with single phonon resonance-continuum depopulation and demonstrate room temperature, CW operation of the proposed 7.9 mum quantum-cascade laser. The laser grown by MOVPE emits a CW output power of 36 mW at 30degC. The proposed structure may lead to successful commercial mass-production of the lasers.