Please select the most similar patent number from A, B, C and D. Which number is?
Disclosed are a laser wavelength measurement device (2) and method. The laser wavelength measurement device (2) comprises: a first optical path assembly and a second optical path assembly, the first optical path assembly and the second optical path assembly constituting a laser wavelength measurement optical path, wherein the second optical path assembly comprises an FP etalon assembly (11) and an optical classifier (13); a homogenized laser beam passes through the FP etalon assembly (11) to generate interference fringes; and the optical classifier (13) is arranged, in the laser wavelength measurement optical path, behind the FP etalon assembly (11) for carrying out deflection processing on the laser beam passing through the FP etalon assembly (11). The FP etalon assembly (11) has two FP etalons (FP1, FP2) sharing the same optical path for interference imaging, is compact in terms of structure, is small in size, and has a simple design and high stability, and in cooperation with the optical classifier (13), same can achieve the precise measurement of a laser wavelength and has a large wavelength measurement range, and is adapted for the on-line measurement of a laser wavelength and corresponding closed-loop control feedback.
A: A method for correcting an air refractive index in large-range absolute distance (D) measurement. Self-correction of the air refractive index in the absolute distance (D) measurement is implemented by using a two-color method based on a single wavelength (λ 1 ) of a laser and a synthetic wavelength. Two laser devices (1, 2) respectively output a laser beam having a fixed wavelength and a laser beam having an adjustable wavelength; a chain of synthetic wavelengths (λ S1 , …, λ Si , …, λ Sn ) from large to small is constructed by a laser interference system (II); each stage of synthetic wavelength meets an inter-stage transition condition, and a minimum synthetic wavelength (λ Sn ) can transition to a single wavelength (λ 1 ); to-be-measured absolute distances (D) are respectively measured to obtain optical distance estimated values (L S1 , …, L Si , …, L Sn ) of which the precision is gradually improved; optical distances (L Sn , L 1 ) corresponding to the minimum synthetic wavelength (λ Sn ) and the single wavelength (λ 1 ) are simultaneously obtained; a corrected absolute distance (D) is obtained according to a two-color method air refractive index correction principle. The present method is applicable to large-range distance measurement and high-precision distance correction, relates to full-path correction of an air refractive index along an actual measurement optical path, and is easily implemented due to low measurement precision requirements for environmental parameters, such as temperature and pressure.
B: An optical system for use in a laser interferometer for measuring the straightness of a guiding rail comprises: a detection optical assembly (1); an optical deflecting mirror (2); a rotatable laser head (3); and an outer light path assembly. The detection optical assembly (1) realizes two-pass optical detection of a light beam passing therethrough. The optical deflecting mirror (2) is used to realize a downward movement and rotation of the light beam so as to adapt to a detection requirement of the detection optical assembly. The rotatable laser head (3) is a rotatable back-reflection element disposed between the detection optical assembly (1) and the outer light path assembly. The outer light path assembly is used to measure an outer light path of an optical system. The optical deflecting mirror (2) simplifies an arrangement and steps for straightness measurement in a vertical direction. The detection optical assembly (1) realizes two-pass optical detection, thereby reducing the number of optical members in the optical system, maximizing utilization of the optical members, and reducing the space required for an instrument. Moreover, the design of a hole for a back-reflected laser beam at the rotatable laser head (3) fully exploits an existing hole and is thus more reasonable.
C: A laser light path system (10) and a projection device, relating to the technical field of projected display. The laser light path system (10) comprises a laser (11), a light combining mirror (12), a loop assembly (13), and a fluorescence assembly (14). The light combining mirror (12) comprises a first region (121) and a second region (122), and an included angle between a light emitting direction (f1) of the laser (11) and a mirror surface of the first region (121) is an acute angle. A light beam (S) emitted by the laser (11) comprises a first light beam (S1) that passes through the first region (121) and is emitted to the fluorescence assembly (14), the fluorescence assembly (14) generates fluorescence (S3) under the excitation of the first light beam (S1) and reflects the fluorescence (S3) to the second region (122), and the second region (122) reflects the fluorescence (S3) towards a light outlet (15). Moreover, the light beam (S) emitted by the laser (11) further comprises a second light beam (S2) reflected by the first region (121) to the loop assembly (13), and the loop assembly (13) reflects the second light beam (S2) to the first region (121) again and emits the second light beam (S2) towards the light outlet (15) synchronously with the fluorescence (S3) through the first region (121).
D: Disclosed is a high-accuracy interference wavelength measuring instrument, comprising an optical input port, a light shield, an off-axis parabolic mirror, a first flat glass, a second flat glass, at least two cylindrical lenses, and at least two linear photodetectors. An isolation frame having a hollow area at the center and having wedge angles is arranged between the first flat glass and the second flat glass so as to form a sealed cavity, and the front surface of the first flat glass and the back surface of the second flat glass are arranged opposite to each other; one side of the front surface of the first flat glass is provided with at least one small flat glass having a thickness and located in the sealed cavity, the other side of the front surface is provided with a first reflective layer, and the back surface of the second flat glass is provided with a second reflective layer. According to the high-accuracy interference wavelength measuring instrument of the present invention, in the case of not increasing the optical path size, the detected spectral range is wide, optical wavelength light of various wavelength types can be accurately measured at the same time, and the pm-level measurement accuracy is achieved.
Answer: D