The new semiconductor laser devices operated only at cryogenic temperatures (typically that of liquid nitrogen, that is, at 77K or –196 °C). For practical use, it would be necessary to demonstrate diode laser action, continuous-wave, at room temperature.
The new semiconductor laser devices operated exclusively at extremely low temperatures (like that of liquid nitrogen, approximately 77K or –196 °C). For practical application, it would be necessary to exhibit diode laser action, continuous-wave, at room temperature.