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 He-Ne laser serial experimental system (LEOI-53) is designed with an adjustable He-Ne laser cavity. By changing the cavity length or the radius of curvature of the cavity output mirror, corresponding change in lasing mode can be observed. The use of a confocal spherical scanning interferometer further allows students to directly observe the frequency distribution pattern of both longitudinal and transverse modes of a He-Ne laser. The scanning interferometer is also used to measure the frequency spacing between laser modes. Other optical parameters such as the spot size and the beam divergence angle of a He-Ne laser, and the free spectral range and the finesse of a scanning Fabry-Perot interferometer can be also measured with this system.
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
