Narrow-linewidth vertical-cavity surface-emitting lasers for oxygen detection

The use of vertical-cavity surface-emitting lasers (VCSEL's) for optical de tection of atmospheric oxygen is described. The VCSEL's were custom designe d for single-mode emission in the 763-nm wavelength range, with low noise a nd narrow optical linewidth. Using standard wavelength modulation spectrosc opy and a second-harmonic detection scheme with a l-m air path, we determin ed an oxygen concentration resolution of 0.2%. Because of its small size, l ow power dissipation, and good tunability characteristics, the VCSEL promis es to be an attractive light source for use in compact, low-cost optical se nsor microsystems for trace gas detection. (C) 2000 Optical Society of Amer ica OCIS codes: 300.6260, 280.3420, 140.3570.