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OXP-20 LED & Laser Diode

  Topics:
Electroluminescence
Semiconductor
Laser Diode
Monochromaticity
Beam Shaping
 

Nick Holonyak,
Born 1928

 


Nick Holonyak developed the first practical LED in 1962. When electrically biased in the forward direction an LED is able to emit light through electroluminescence. The colour of the emission depends on the semi conducting material used, and can be near-ultraviolet, visible or infrared. The semi conducting chip is encased in a solid plastic lens, which is much more resistant than the glass envelope of a traditional light bulb or tube. Most typical LEDs are designed to operate with no more than 30-60 mill watts of electrical power.
Around 2000, commercial LEDs capable of continuous use at one watt of input power were introduced. Nowadays 10 watt units will be available with efficiencies of 60 lumens per watt. These devices produce light similar to a 50 watt light bulb, and facilitate the use of LEDs for general illumination needs. The typical working lifetime of an LED is ten years, which is much longer than the lifetimes of most other light sources.
Rober Hall is usually cited as the inventor of the semiconductor laser, but Holonyak was involved in the development as well. In laser diodes, light is generated basically on the same principle like in LEDs. But by especially designed semiconductor material laser operation is achieved rather than spontaneous luminescence.
Within this experiment, properties of LEDs and Laser Diodes like current dependency, spectral and beam characteristics are investigated. The polarization state of the light emitted by the diodes is determined and beam shaping experiments are performed.




 

Examples of Investigation and Measurement


Current dependency of LEDs and Laser Diodes
The dependency of the emitted light intensity on the electrical current is investigated. Therefore several LEDs and a laser diode are provided.

Beam properties and polarization of LEDs and Laser Diodes
The strongly divergent beams of LEDs and laser diodes are investigated concerning opening angle and ellipticity. With special lenses beam shaping is performed to achieve special beam profiles like for example laser lines.

Spectral properties of LEDs and Laser Diodes
Although based on the same principle of light generation the spectral characteristics of LEDs and laser diodes are very different. By means of an optical grating it shows that the spectral range of LEDs exceed the range of laser diodes by far. Especially the spectrum of white light LEDs is expanded over the whole visible range contrasting the almost monochromatic laser light.


 


 

 

 

 

OXP-20   Required Equipment


1  
 


02.0500
 

 


Profile rail OCM 650, 500 mm

The high precision optical rails are made out of special anodized aluminum. The rails are the base for various modules attached to carriers.
 




 

1

02.1022

Carrier OCM 650, 20 mm with screen holder

This module can mount optical screens. Through the attached carrier, the screen holder can be placed onto the optical rail. The carrier 20 mm and the holder are made out of special anodized aluminum.
 

1

02.1024

Carrier OCM 650, 20 mm with attached plate holder

Using a spring loaded blade 50 x 50 mm, plates like filters or gratings can be fixed onto this module. The carrier allows the direct attachment to the optical rail. The carrier 20 mm and the holder are made out of special anodized aluminum.
 

1 02.1602

Screen with scale

Experimental results like colour spectra and interference patterns can be visualized on these screens. Horizontal or vertical scales allow calibrations and quantitative measurements; a screen with an aperture is used for observing back-reflected rays. The screens are made out of anodized aluminum plates with one side painted white and can be fixed onto screen holders (02.1022, 02.1608).
 

1
3

02.2126
02.2132

Mounting plate OCM 650 for click 25, including carrier 20 mm
Mounting plate OCM 650 for click 30, including carrier 20 mm

Mounting plates are used to hold optical mounts. A characteristic feature of the mounting plates is the “click” mechanism of the inserts based on spring loaded spheres. Snapping in the groove of the inserted click mount, the optical element is kept in an exact position. On the other hand, the system allows a quick and easy change of the mounted inserts.
The mounting plates are made out of special anodized aluminum. Mounted onto the carrier 20 mm, the mounting plates can be placed onto an optical rail.
 

1 02.6106

4 axis adjustment holder KH650, theta, phi, X and Y, including carrier 20 mm

This adjustment holder mounts a Diode Laser or an LED lamp. Using the fine pitch adjustment screws, the optical axis can be aligned within the range of 3 mm. For fine alignment of the angle of the light beam, two additional pitch adjustment screws are attached onto the back of the holder. The holder and the carrier 20 mm are made out of special anodized aluminum and can be placed onto an optical rail.
 

1
1
1
 
04.0060
04.0090
04.0092
 

Plano convex lens f=40 mm, mounted in click 30 mount
Cylindrical
lens f=25 mm, mounted in click 30 mount
Cylindrical
lens f=80 mm, mounted in click 30 mount

Different glass lenses are mounted onto a special anodized aluminum click mount 30 mm by two threaded mounting rings to be used in connection with a mounting plate (02.2132).
 

1 04.0702

Optical grating, 600 lines / mm

This optical grating copy mounted between two glass plates is used for generating a spectrum of the investigated light.
The frame has a size of 50 mm x 50 mm x 2,5 mm and the grating window is 35 mm x 24 mm large.
 

1 05.0030
05.0032
05.0038

LED white in housing
LED red in housing
LED blue in housing

As universal and easy-to-change light sources, LED lamps are used in optical experiments. The LEDs are mounted onto a 40 mm x 25 mm diameter housing tube made out of special anodized aluminum. For the alignment, the lamps can be fixed onto a four axis adjustment holder mounted onto a carrier. For their operation, the active LDD-05 power supply (07.0206) is required which controls the output power. For the lamps 1 W (white LED: 3W), high brightness LEDs are used.
 

1 05.0232

DIMO diode laser module, 630 nm (red)

Due to its divergin beam, this red laser diode is used for beam shaping experiments. The laser diode in its 40 mm x 25 mm diameter housing tube, made out of special anodized aluminum, can be fixed onto a four axis adjustment holder and can be aligned to the optical axis. Driven by the LDD-05 active power supply (07.0206), the output power is controlled in the range from 0 to 3 mW.
 

1 07.0010

BNC – Banana adapter connection leads 2x4 mm plugs

This BNC cable is used to connect a photodetector (07.0101) to a digital multimeter (19.0400).
Total length: 1 m

1 07.0102

PIN Si Photodetector BPX 61 complete with housing

Using a BNC cable, the photodetector can be connected to a measuring device. Mounted onto a special anodized aluminum click 25 head, the photodetector is to be used in connection with a mounting plate (02.2126).

1 07.0206

LDD-05 active power supply

The universal LDD-05 active power supply is used for all laser and LED light sources. It recognizes which source is connected and sets the parameters for it automatically. The unit is equipped with a main switch, a regulation knob for adjusting the laser or LED power and a safety lock. The provided USB bus interface allows control through a personal computer or laptop and qualifies this unit as multimedia source.
The housing is made out of shock-proof plastic with an aluminum front and rear panel.

Voltage: 230 VAC / 50 Hz
Case dimensions: 200 mm x 160 mm x 62 mm.
 

 

1 09.0044

Module polarization analyzer with mounting plate and rotation assembly

In this unit, the high quality polarizer foil is inserted into a rotatable holder mounted onto a carrier. Using the rotating insert, the polarization direction can be set in degrees (0 - 360°) with a resolution of 2°. The unit is made out of special anodized aluminum. Mounted onto the carrier 20mm, it can be directly attached to the optical rails.

1 19.0400

Digital multimeter 3 ˝ digits

he digital multimeter is used for relative intensity measurements of light beams. It has to be connected to a photodetector via banana adapter connection leads.

Specifications:

Display LCD, 3 ˝ digits  
AC voltage ranges 2 / 20 / 200 / 750 V
Frequency range 40 - 400 Hz
DC voltage ranges 0,2 / 2 / 20 / 200 / 1000 V
AC current ranges 2 / 20 / 200 mA / 20 A
Frequency range 40 - 400 Hz
DC current ranges 0,2 / 2 / 20 / 200 mA / 20 A
Resistance ranges 0,2 / 2 / 20k / 0,2 / 2 / 20 MΩ.



 

 




 


 


 




 

 

Experiments

OXP-01 Refraction of Light

OXP-02 Prisms

OXP-03 Lenses

OXP-04 Reflection & Transmission

OXP-05 Beam Bending

OXP-06 Refractometer

OXP-07 Diffraction of Light

OXP-08 Optical Gratings

OXP-09 Spectral Analysis

OXP-10 Interference

OXP-11 Interferometer

OXP-12 Holography

OXP-13 Polarisation

OXP-14 Double Refraction

OXP-15 Colour Mixing

OXP-16 Optical Filters

OXP-17 Absorption & Emission

OXP-18 Image Projection

OXP-19 Camera

OXP-20 LED & Laser Diode

 

Kits

Basic Kit

Complete Kit

Advanced Kit