AlGaAs laser diode

For applieation (see below) the ions are irradiated with a laser diode (Sect. 10.4) Er " absorbs 800 nm from an AlGaAs laser diode, Tm absorbs 650 nin from newly developped laser diodes. Ftgure 10.5 shows that the ion reaches the green-emitting level by subsequently absorbing two photons. Two different pathways are indicated their relative importance depends on the ratio of the different transition rates. Also the Tm ion reaches the blue emitting Dj and O4 levels by a two-step process. In both cases a quadratic dependence of emission intensity upon excitation power has been observed [6]. 

Another method of increasing the modulation bandwidth is to decrease the photon lifetime. This is most easily accomplished by decreasing the laser diode cavity length. This, however, increases the laser threshold current level, and as a result, lasers with extremely low threshold current levels are required for this method. Utilizing a 40-/rm-long AlGaAs multiple quantum well laser, a modulation bandwidth of 50 GHz has been achieved. 

Operation with laser diodes simply requires construction of a cell of the same configuration as above, but with the dielectric stack reflectivity centered to match that of the gold at the wavelength used. Thus we were able to demonstrate laser diode driven optical bistability using the AlGaAs laser output from a demounted compact disk player read arm (Fig. 3). The higher critical switch power of 62.5 /iW is due to the larger spot size of 117 //m ( /e diameter) used. 

The applications of these laser diodes are numerous in construction technology of CD Player (GaAs), of LASER printers (AlGaAs) and in... 

P. Zory and L. D. Comerfold, Grating-coupled double-heterostructure AlGaAs diode lasers, IEEE J. Quant. Electron QEll, 451-457 (1975). 

Lasers and LEDs. Dye lasers pumped by Ar ion, Cu ion and frequency doubled Nd YAG solid state lasers. LEDs operating at 635-652, diode lasers at 635 (AlGalnP), 652 (InGaAlP) and 730 mn (AlGaAs). Solid state pulsed lasers, (e.g. Nd YAG, Nd YLF) operating at second, third and fourth harmonic generation. 

The communications revolution also relies on a diverse set of CVD technologies. Some components are similar to those used in silicon microelectronics, but many are unique, involving complex epitaxial heterostructures of SiGe or compound semiconductor (e.g., AlGaAs) alloys that are required to yield high frequency (1-100 GHz) device operation. The communication revolution also relies on optoelectronic components, such as solid state diode lasers (another complex heterostructure device), and these devices are often grown by CVD. - Even the fiberoptic cables that transmit the optical component of the communications network are manufactured using a CVD technique to achieve the desired refractive index profile. ... 

Acetylene and methane can be detected in remote locations using diode lasers coupled with optical fibres Environmental measurements of acetylene are possible based on the overtone transition at 2 789 nm, using a stabilized AlGaAs diode laser, operating in an external optical cavity configuration. The detection limit is 0.2ppm/km for acetylene... 

However, the power of the diodes was too low and the absorption of the 1 at.% Nd YAG at this level was too weak, with an absorption coefficient of about 4 cm Therefore, it was later changed to pumping into the strong absorption of %/2 " Fs/2 at about 809 nm, having an absorption coefficient of about 11.4 cm by using more efficient and powerful AlGaAs diode lasers. In this case, a relative quanffim defect of 0.24 was observed for the laser emission at 1.06 pm, about 30 % of which represented the upper part, without having any effect on the laser emission. 

F.S. Pavone, M. Inguscio, Frequency- and wavelength-modulation spectroscopy Comparison of experimental methods, using an AlGaAs diode laser. Appl. Phys. B 56, 118 (1993)... 

Figure 4.18 Typical output spectrum from an ALGaAs diode Laser, as a function of injection current (Left) and temperature (rigiit) multi-mode operation at Low injection current and single-mode operation at liigh injection current are indicated in the insets. Mode-hop Locations are marked by the arrows...

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