High-frequency intensity noise of lead-salt diode lasers.

The high-frequency intensity noise spectra of mid-infrared diode lasers have been investigated. Theoretical estimates are compared with experimental results of spectral noise measurements. Lasers with different lateral structures showed comparable characteristics, although at different noise levels. Relative intensity noise as small as 10-17 Hz-1 was observed; this is close to the quantum noise limit for detection and hence suitable for trace-gas analysis systems.