G5U-PH Laser Interferometer

This shearing-interferometry instrument provides simple, intuitive assessment of laser-beam parallelism as a reference for laser alignment or laboratory optical-path adjustment. Beam collimation is calculated from fringe rotation relative to a horizontal baseline, while fringe shape reveals the original wavefront's aberration distribution. It is both a beam-collimation tester and a qualitative wavefront analyzer. Principle:a high-quality optical flat of finite thickness and slight wedge angle divides a spatially coherent wavefront into two identical, mutually displaced wavefronts. Coherence produces interference in their overlap (Figure1). Figure1:schematic of shearing interference. The wedge direction is perpendicular to the shear. A perfectly parallel beam produces fringes parallel to the shear; convergence or divergence rotates them (Figure2). Figure2:shearing interferograms for different beam states. Wavefront aberrations bend the fringes in characteristic ways, allowing qualitative identification of aberration type and magnitude. Measurement method: 1. Collimation assessment:observe fringe tilt on the receiving screen as in Figure2. Fringes parallel to the baseline indicate collimation; upward tilt indicates divergence and downward tilt convergence. For a nonparallel beam, the rotation angle gives divergence. Figure3 shows the calculation method. Figure3:beam-divergence calculation. The source introduces formulas for curvature radius and divergence without displaying them in this text. Incident diameter d and wavelength are known; shear is available from catalog specifications. Fringe spacing depends on wavelength and wedge angle and can be read from the catalog or measured. Fringe rotation is measured using an optional graduated receiver. Substitution into equations(1) and(2) yields wavefront curvature radius and divergence. 2. Aberration assessment:compare with the referenced interferograms. Figure4:spherical aberration at different defocus positions, (a)inside focus, (b)at focus, (c)and(d)outside focus. Figure5:coma, (a)without defocus, (b)with slight defocus. Figure6:astigmatism, (a)sagittal shear, (b)tangential shear.

Laser Center Wavelength: 633nm Output Power: 2mw Coherence length: >50m

Because lasers have good coherence, measuring a plane-parallel optical element produces interference fringes between its front surface and the interferometer reference, between its rear surface and the reference, and between the front and rear surfaces themselves. These three fringe sets overlap, and conventional methods cannot directly analyze such an interferogram. A common approach is to coat the sample's rear surface with grease such as petroleum jelly. With a refractive index close to1.5, similar to most optical glasses, the grease acts like a roughened rear surface and removes unwanted rear-surface interference. However, it risks contaminating the sample and is ineffective for high-index optical glass. Multi-surface measurement technology (MST) provides a solution. It uses a wavelength-tunable laser: wavelength-induced phase shifts depend on cavity length, giving each fringe set from a plane-parallel optical element a unique cavity-length-related frequency. By analyzing a single acquired dataset, Shineoptics' multi-surface measurement algorithm independently separates the profiles of the parallel surfaces. A single measurement therefore directly yields three characteristics: front-surface figure, rear-surface figure, and optical-thickness variation.

Interferometer Aperture: 152mm Maximum Test Aperture: 300mm Light Source: Frequency-Stabilized Helium-Neon Laser

The name Guyu refers to rain nourishing the hundred grains: plentiful, timely rainfall allows grain crops to thrive. Amid unprecedented changes of the past century, Shineoptics named the new product Guyu to express its wish that the company's pioneering spirit and innovation would help Chinese optics overcome foreign product sales bans and achieve independence, and that the Guyu series would become a vital source of the company's continuing progress. The Guyu 300 spherical stitching laser interferometer, released by Shineoptics in 2022, is the first product in the Guyu series. The Guyu 300 uses an integrated air-float vibration-isolation structure. Computer software automatically plans the stitching scheme, and a computer-controlled 5-axis mechanism locates images and automatically performs stitching measurements. Dedicated Sirius stitching-interferometer software then processes the data for high-precision surface-figure error measurement. For applications including lithographic objectives and ultraviolet microscope objectives, the Guyu 300 helps customers measure full-size surface-figure errors of 300mm-aperture convex lenses, hemispherical lenses, and spherical lenses.