1152nm wavelength helium neon laser nano-measuring tape

Abstract

A nanometer measuring tape for helium-neon lasers with the wavelength of 1152 nm belongs to the technical field of laser-based displacement sensing, and is characterized in that the prior helium-neon laser with the wavelength being 632.8 nm is substituted for the helium-neon laser with the wavelength being 1152 nm to serve as the core of a nanometer measuring tape, so that the measuring range of the displacement is increased from 50 nm to higher than 100 nm under the condition that the resolution ratio (10 nm) remains unchanged. As the helium-neon laser with the wavelength being 1152 nm has higher gain, gain can be kept greater than loss when the inner cavity of the laser is exposed to air, therefore, the non-contact measurement of the separation between a gain pipe and a target lens is realized. By adopting a cat' s eye reflector as a target lens to be stuck with a target to be measured and designing the nanometer measuring tape into two structures with a full outer cavity and a semi-outer cavity respectively, the system has stronger stability, thereby becoming a steady and practical displacement sensor.

Description

Technical field [0001] The invention relates to a helium-neon laser nanometer ruler with a wavelength of 1152nm, belonging to the technical field of laser displacement sensing. Background technique [0002] Chinese patent "Displacement self-sensing helium-neon laser system and its realization method" (application number: 99103514.3) comprehensively utilizes laser frequency splitting, laser mode competition, laser power tuning and other laser physical phenomena to transform an ordinary helium-neon laser It becomes a displacement sensing instrument with self-calibration function. This method has a range of 12mm and a displacement measurement resolution of λ / 8 (for a HeNe laser with a wavelength of 632.8nm, λ / 8 is 79.1nm). The main structure of this invention is a 632.8nm wavelength semi-external cavity He-Ne laser, one of its two reflecting cavity mirrors is fixed on a linear guide (rod) as a moving mirror to avoid axial movement along the optical axis of the laser Time cavity is d...

AI Technical Summary

Problems solved by technology

However, if the measurement range is required to be further improved, or to realize non-contact measurement, the displacement sensor with the He-Ne laser at the wavelength of 632.8nm as the core has been unable to achieve

Due to the limitations of the principle, if the measuring range is increased, the laser will have two longitudinal modes and four frequencies or even three longitudinal modes and six frequencies, which will make the signal processing system unable to work normally; The straightness of the movement of the cavity mirror, so the expansion of the measuring range is restricted

Due to the small gain of the helium-neon laser with a wavelength of 632.8nm, when a cavity mirror is used as a target mirror to move with the target object, there will be a phenomenon that the laser cannot output laser light due to the gain of the laser being less than the loss, so it is difficult to realize non-contact measurement

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