1. Adjustment experiment of helium neon laser resonant cavity;
2. Adjustment experiment of confocal spherical scanning interferometer;
3. Measurement experiment of equivalent cavity length of helium neon semi external cavity;
4. Laser transverse mode transformation and parameter measurement experiment;
5. Observation experiment of longitudinal mode orthogonal polarization and mode competition of helium neon laser;
6. Laser Gaussian beam parameter measurement experiment (Gaussian intensity distribution, centroid position, Rayleigh length, far-field divergence angle, M2 factor, waist position, and waist width);
7. Laser transverse mode transformation (single transverse mode, multiple transverse modes) and parameter measurement experiment;
8. Gaussian beam transformation (collimation, beam expansion, focusing) and measurement experiments;
9. Laser resonant cavity design experiment (parameter measurement under different cavity lengths, cavity mirror curvature radii, and F parameters of the laser).

Knowledge points

The basic components of a laser, laser working material, pump source, optical resonant cavity, laser power, laser transverse mode, laser longitudinal mode, polarization state, orthogonal polarization, Gaussian beam parameters (diameter, waist, divergence angle), Gaussian beam transformation, confocal spherical scanning interferometer, and free spectral region.

Optional equipment parameters

1. Computer (basic configuration).
2. Digital oscilloscope: bandwidth 100MHz, sampling frequency 1GHz.

Main equipment parameters

1. Light source components:

1-1 helium neon laser: wavelength 632.8nm, P>1.5mW，TEM00， Fully protected high-voltage plug with dual switch design (safety key, button), compliant with CE requirements;

1-2 Variable Mode Helium Neon Laser: Gain tube length 270mm, Brewster window, achievable modes including TEM00, TEM01, TEM10, TEM11, etc.

2. F-P confocal spherical scanning interferometer component:

Fine constant>100, free spectral region 2.48GHz; The linearity of the sawtooth generator is less than 10%, the sawtooth voltage range is 0-150V, the bias voltage is adjustable from 0-150V, the frequency is adjustable from 0-100Hz, the detector bandwidth is 1MHz, and the primary signal is amplified.

3. Spot parameter measurement and calculation system:

3-1 Spot centroid position, one-dimensional light intensity distribution curve, two-dimensional pseudo color display of energy distribution, three-dimensional stereoscopic display, horizontal and vertical width of the spot.

3-2 can calculate the beam waist width, beam waist position, far-field divergence angle, M2 factor, and Rayleigh length of the light spot, USB 2.0 software lock.

4. Optical components:

Polarizer: Φ 25.4mm, K9 glass window, AR@400nm ~700nm, extinction ratio>400:1; Gaussian beam transformation lens: Φ20mm～40mm，f=50.8mm～150mm， Grade III smoothness; Attenuation film: transmittance T=0.2-10%; Narrowband filter: Half wave width of 50nm.

5. Detector components:

Programmable power meter: The display screen shows the measurement wavelength, automatic/manual range mode, attenuation window status, and current power measurement gear; The host displays a frequency of 300mS/time, with a measurement accuracy of 0.1 μ W and a resolution of 0.1 μ W, supporting six range measurement; Measurement wavelength range of 200nm-1100nm, power measurement range of 0-40mW (bare detector)/0-2W (attenuation window); Provide real-time power display, long-term power detection, and display the measurement duration and power change curve within the measurement time. Provide maximum, minimum, and mean display, and export Excel data. Users can set the power alarm range and provide alarm prompts for exceeding the limit; USB 2.0 remote operation communication interface. CCD camera: resolution 1292 * 964, quantization depth 12 bits, pixel size 3.75 μ m × 3.75 μ m, miniUSB 2.0 interface.

6. Mechanical components:

Precision optical guide rail: L × W=1200mm × 90mm, equipped with slider, one-dimensional moving slider, adjustable support, and support rod; High precision adjustment mirror frame; CCD variable attenuation aperture: C interface; Two dimensional adjustable prism holder; Laser tube holder, adjustable in two-dimensional pitch, with a maximum clamping capacity of 50mm.

7. Experimental manual and warranty card.