Long distance microvibration measurement usingexternal-cavity semiconductor laser

With Littrow-type external-cavity grating and temperature controlling, the spectral line width is compressed to be less than 1.2 MHz (Δλ3.5×10~(-6) nm), while the original linewidth of the semiconductor laser is broader than 1200 GHz. Based on this, the system for measuring the amplitude and frequency of the microvibration with sinusoidal modulation is designed, detecting effect is good.