Apparatus for Characteristic study of Diode Laser

Apparatus for Characteristic

study of Diode Laser

Model : HO-ED-LOE-01

Holmarc's Apparatus for Characteristic Study of Diode Laser (Model No: HO-ED-LOE-01) is an important educational instrument for the study of beam profile with the detector mounted on XYZ translation stage and the diode laser. In this apparatus, the detector is scanned linearly using a translation stage along the cross section of laser beam noting down the intensity readings at close intervals.

A graph is plotted from the readings for finding out attributes like Gaussian nature, divergence etc. The laser diode is designed to produce a cone of divergent radiation with an elliptical cross-section and Gaussian intensity distribution.

For studying polarization nature of the laser beam, diverging laser output is made to pass through a polarizer which is fixed on a rotary mount with graduations. Using the detector and readout, intensity at various rotary positions of the polarizer is tabulated. The degree of polarization varies with the diode current.

Experiment Examples

To study gaussian nature of the laser beam

Study the intensity distribution of laser in X and Y direction using the corresponding micrometer of XYZ stage. The beam is scanned linearly using the micrometer noting down the output current of the detector at close intervals. Plot the detector current Vs distance graph and can study the gaussian nature of the laser beam.

To find diameter (beam spot size) of the laser beam

The 'Beam Diameter' is defined as "The distance across the center of the beam for which the irradiance (E) equals ( 1 / e² = 0.135 )". The 'Spot Size' (ω ) of the beam is "The radial distance (radius) from the center point of maximum irradiance to the 1 / e² point". These definitions provide standard measures of laser beam size.

To determine divergence of the laser beam

Divergence angle θ is given by,

θ = tan^-1 ( | ω₂ - ω₁ | )

Where ω₁ and ω₂ are the beam spot sizes at two different positions say Z₁ and Z₂ respectively.

To study polarization nature of the laser beam

Plot a graph with polarizer angle and the output current from the detector and can study the polarization nature of the laser beam.

Specifications

Laser type : Diode laser (Red)

Input : 230V AC / 50 Hz

Output power : 3 mW

Wavelength : 650 nm

Features

Laser assures smooth switch on and long life

Light sensor range 0-199 milli / micro amperes

Linear travel of 25mm for XYZ axis

Precision micrometer driven translation stage with resolution of 10 microns

Related Topics

Gaussian nature

Polarization nature

Beam spot size

Laser beam divergence