Gain curve and longitudinal modes
Modes shown on digital oscilloscope
Setup for measuring the spot size and beam divergence of He-Ne laser
Note: oscilloscope not included
Features
Including Additional He-Ne Alignment Laser
High Resolution
Ideal for Demonstration
Precise Measurement
Introduction
The LEOI-53 He-Ne Laser Serial Experimental System is designed to provide students with a comprehensive understanding of He-Ne laser resonators and their modes. This system offers the flexibility to adjust the He-Ne laser cavity by modifying the cavity length or the radius of curvature of the output mirror, enabling students to observe the corresponding changes in the lasing mode. The system also incorporates a confocal spherical scanning interferometer, which is used to directly observe the frequency distribution pattern of both longitudinal and transverse modes of the He-Ne laser.
This experimental setup provides an in-depth exploration of various optical parameters and enables students to conduct precise measurements, such as the frequency spacing between laser modes, spot size, beam divergence angle, and more.
Using this system, students will be able to:
1. Observe and Understand Lasing Modes:
Adjust the He-Ne laser cavity to observe how changes in cavity length and mirror curvature affect the lasing mode.
2. Explore Longitudinal and Transverse Modes:
Use the confocal spherical scanning interferometer to directly observe the frequency distribution patterns of both longitudinal and transverse modes of the He-Ne laser.
3. Measure Mode Spacing:
Measure the frequency spacing between different laser modes using the scanning interferometer.
4. Analyze Optical Parameters:
Measure and analyze important optical parameters of the He-Ne laser:Spot size, Beam divergence angle, Free spectral range (FSR), Finesse of the scanning Fabry-Perot interferometer.
The instruction manual contains comprehensive materials including experimental configurations, principles and step-by-step instructions. Please click Experiment Theory and Contents to find more information about this apparatus.
Specifications
| He-Ne Laser Cavity with Brewster Window | |
| Radii of Curvature of Cavity Mirrors | R1=∞ or R1=1 m; R2=1 m |
| Cavity Length | 270 mm |
| Center Wavelength | 632.8 nm |
| Output Power | ≤ 1.5 mW |
| Confocal Spherical Scanning Interferometer | |
| Cavity Length | 20.56 mm |
| Radius of Curvature of Concave Mirror | 20.56 mm |
| Reflectivity of Concave Mirror | 99% |
| Finesse | >100 |
| Free Spectral Range (FSR) | 3.75 GHz |
Sawtooth Wave Generator | |
| Modulation Amplitude of Sinusoidal Wave | 0 ~ 250 V, continuously adjustable |
| DC Offset Voltage Output | 0 ~ 250 V, continuously adjustable |
| Output Frequency | 20 ~ 50 Hz |
| He-Ne Laser for Beam Alignment | |
| Center Wavelength | 632.8 nm |
| Output Power | ≤ 1 mW |
| Optical Rail | 1 m; aluminium |
Optical Power Meter | 2 µW ~ 200 mW, 6 scales |
Part List
| Description | Qty |
| Optical Rail (LEPO-54) | 1 |
He-Ne Laser for Beam Alignment (LLL-2A) | 1 |
| Semi-External Cavity He-Ne Laser | 1 |
| He-Ne Laser Power Supply | 1 |
| Output Mirror | 1 |
| Four-Axis Adjustable Holder (SZ-24) | 2 |
| Two-Axis Adjustable Holder (SZ-06) | 2 |
| Alignment Aperture | 1 |
| High Speed Photo-Receiver | 1 |
| Confocal Scanning Interferometer | 1 |
| High-Voltage Sawtooth Wave Generator | 1 |
| Optical Power Meter (LLM-2) | 1 |
| Adjustable Slit (SZ-27) | 1 |
| 2-D Adjustable Holder (SZ-07) | 1 |
| Plane Mirror | 1 |
| Tape Measure | 1 |
| User's Manual | 1 |
Gain curve and longitudinal modes
Modes shown on digital oscilloscope
Setup for measuring the spot size and beam divergence of He-Ne laser
