Physics Lab Equipment

LEOI-57 Apparatus for Properties Measurement of Semiconductor Laser

LEOI-57 Apparatus for Properties Measurement of Semiconductor Laser


  • Rich experimental contents

  • Convenient in operation

  • Stable & reliable experimental performance

  • Complete system


Semiconductor lasers, using semiconductor materials as working substances, are similar to gas and solid lasers that in principle have the basic structure composed of working substance, resonant cavity and excitation energy source. The main working substances of semiconductor lasers include GaAs, MoSb, ZnS, CdS and so on. The cleavage planes of a semiconductor crystal are generally used as mirrors to form a resonant cavity. Commonly used excitation energy sources include electrical injection, light stimulation, high-energy electron beam excitation and collision ionization excitation. To generate laser emission, the Gain Condition and Threshold Condition must be met. The output wavelength range of semiconductor lasers is relatively wide, generally from 0.3 microns to 30 microns. Owing to these excellent characteristics of small size, high efficiency, long life and high-speed modulation ability, semiconductor lasers have an extremely wide range of uses.

LEOI-57 apparatus for measuring characteristics of semiconductor laser consists of a suitcase (including temperature control device, display of angle sensor, laser power meter, laser power supply, voltmeter, etc.), semiconductor laser device (including heating device, cooling fan, and angle sensing device, etc.), slide rail, polarizer and analyzer, optical power detector, and so on. It is designed to measure the electrical and optical characteristics of a small-power semiconductor lasers (optical power less than 2 mW). The apparatus has features of rich experimental contents, convenient in operation, stable and reliable experimental performance. 

Using this apparatus, students can conduct the following experiments on a semiconductor laser:

1. Measure the far-field distribution of the beam and calculate its vertical and horizontal divergent angles. 

2. Measure the voltage-current characteristics.

3. Measure the relationship between output optical power and current, and acquire its threshold current. 

4. Measure the relationship between the output of optical power and current at different temperatures, and analyze its temperature characteristics.

5. Measure the polarization characteristics of the output light beam and calculate its polarization ratio. 

6. Optional experiment: verify Malus's law.

The instruction manual contains experimental configurations, principles, step-by-step instructions, and examples of experiment results. Please click Experiment Theory and Contents to find more information about this apparatus.



Semiconductor Laser 

Output Power< 2 mW
Center Wavelength: 650 nm

Power Supply of Semiconductor Laser

0 ~ 4 VDC (continuously adjustable), resolution 0.01 V
Photo DetectorSilicon detector, aperture of light entrance 2 mm
Angle SensorMeasurement range 0 - 180°, resolution 0.1°
Polarizer  Aperture 20 mm, rotation angle 0 - 360°, resolution 1°

Light Screen

Size 150 mm × 100 mm
VoltmeterMeasurement range 0 - 20.00 V, resolution 0.01 V

Laser Power Meter 

2 µW ~ 2 mW, 4 scales
Temperature ControllerControl range: from room temperature to 80 °C, resolution 0.1 °C

Part List

Main suitcase1
Laser support and angle sensing device1 set
Semiconductor laser1
Slide rail1
White screen1
Support of white screen1
Photo detector1
3-core cable3
5-core cable1
Red connection wire (2 short, 1 long)3
Black connection wire (medium size)1
Black connection wire (large size, 1 short,  1 long)2
Power cord1
Instruction manual1


Horizontal intensity distribution


Vertical intensity distribution


V-I characteristic curve


P-I characteristic curve


P-I characteristic curves under various temperatures

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