在精密测量领域,HeNe激光器是制造激光干涉仪的首选.但能够产生中频差4—40 MHz的双折射-塞曼双频HeNe激光器的频差是随机的,小到几百kHz,大到十几MHz.为了让频差能够满足制作双频激光干涉仪的要求,曾出现过弹性加力法、钻孔应力调节法等调整和频差赋值的方法.但这些方法在实际应用中都不是很理想.采用激光内雕法赋值频差,通过在激光器的平面输出镜内部雕刻出不同图案,使平面镜内部产生满足要求的相位延迟,达到为频差赋值的目的.激光内雕法有很多优点:不损害激光器,美观;功率损失小,出光强度可接近原始光强度;可反复赋值,频差在0—60 MHz范围内可调整;频差的稳定性好,采用稳频措施后频差的波动范围小于每小时10 kHz. In the field of precision measurement, HeNe lasers are the first choice for laser interferometers, but the birefringence-Zeeman dual-frequency HeNe lasers that produce mid-frequency differences of 4-40 MHz are random, as small as a few hundred kHz and as large as ten A few MHz. In order to make the frequency difference to meet the requirements of the production of dual-frequency laser interferometer, there have been methods such as elastic force method, drilling stress adjustment method adjustment and frequency difference assignment, but these methods are not very practical Ideal.Through the laser inner-engraving method, the frequency difference is assigned, and different patterns are engraved inside the plane output mirror of the laser to make the phase delay within the plane mirror meet the requirement of frequency difference assignment.Laser inner sculpture has many advantages: No damage to the laser, beautiful appearance; small power loss, the light intensity can be close to the original light intensity; can be repeatedly assigned, the frequency difference can be adjusted in the range of 0-60 MHz; the stability of the frequency difference is good; The range is less than 10 kHz per hour.