High-efficiency diode lasers at high output power

Abstract

Demonstration of a visible laser on silicon using Eu-doped GaN thin films J. Appl. Phys. 98, 056108 (2005); 10.1063/1.2037867 Asymmetric, nonbroadened large optical cavity waveguide structures for high-power long-wavelength semiconductor lasers J. Appl. Phys. 97, 123103 (2005); 10.1063/1.1928309High-differential-quantum-efficiency, long-wavelength vertical-cavity lasers using five-stage bipolar-cascade active regions Appl. Phys. Lett. 86, 211104 (2005); 10.1063/1.1931060 High slope efficiency, "cascaded" midinfrared lasers with type I InAsSb quantum wells

Impact of thermal annealing on internal device parameters of GaAs 0.965 Bi 0.035 /GaAs 0.75 P 0.25 quantum well lasers

“…The extracted α i values (11-14 cm −1 ) reported in this paper are in good agreement with the reported value (10-15 cm −1 ) [32]. Nevertheless, these α i values are significantly higher than that of the reported highperformance strained InGaAs QW lasers [31,33]. These high α i values can be ascribed to free carrier absorption [34,35], which results from very high carrier densities within the active region [19], associated with high laser threshold current densities, and therefore high transparency current densities of the devices.…”

“…4a, where a gradual decrease in η 0 d was observed while α i remained nearly constant as the annealing time increases. It must be noted that the overall η 0 d values were significantly lower, while α i values are higher than those typically observed in highperformance InGaAs QW lasers with similar emission wavelengths [31]. These low η 0 d values are partially ascribed to strong carrier leakage resulting from the graded Bi concentration within the GaAs 0.965 Bi 0.035 QW, which has been observed by Z-contrast scanning transmission electron microscopic analysis [11].…”

“…Furthermore, η i d is often assumed to be the same as the injection efficiency at threshold (η inj ) and the extracted η 0 d value from CLA is then used to obtain the transparency current density (J tr ). This common practise does not apply to the present structures since η inj can be very different from η 0 d [30,31], resulting in an inaccurate J tr . Nevertheless, CLA can ), modal material gain (Γg 0J ) and the ratio of J tr /η inj , provided precautions are taken to avoid extraction of data when carrier unclamping is significant.…”

<title>Path toward a high-energy solid-state laser</title>

“…For example, single emitter efficiencies at 940 nm up to 66% have been reported. [8][9][10] Going from this to the program goal will no doubt require optimizing every facet of the diode design -materials and structures. This new program will bear watching, as results reach the publishable stage.…”

Multi-LED package design, fabrication and thermal analysis

“…Improving the heat dissipation from the LEDs is crucial for reducing the LED junction temperature. The temperature is the primary factor influencing the total lifetime, the power efficiency and droop of LEDs [3][4][5]. Modelling the thermal performance of electronic systems and optimization of the design, is becoming a useful tool which can reduce the development time and improve the quality of the final product.…”