21. The combination of GMA-welding and a diode laser leads to a cheap and energy efficient process. 22. For practical use, it would be necessary to demonstrate diode laser action, continuous-wave, at room temperature. 23. The first heterojunction diode lasers were single-heterojunction lasers. 24. The first diode lasers were homojunction diodes. 25. A specific type of laser called the semiconductor diode laser is used to read an optical disc. 26. Single spatial mode diode lasers can be designed so as to operate on a single longitudinal mode. 27. In the very early 1990s, SDL, Inc . began supplying high power diode lasers with good reliability characteristics. 28. This procedure enforces diode lasers are the two most important types of lasers where active mode-locking are applied. 29. In comparison, diode lasers can only reach a few hundred milliwatts unless they operate in multiple transverse mode. 30. The asphere's more complex surface profile can reduce or eliminate spherical aberration and also reduce other collimating diode lasers .
