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Collimating and Focusing Lenses for Laser Diodes
While glass lenses are preferred, there are several product applications where a high quality plastic lens can be effectively utilized. The 300 Series plastic aspheric collimating and objective lenses offer a lower cost alternative to glass and still perform well over a temperature range actually exceeding the upper limit for most laser diodes. Plastic lenses are used in products such as laser pointers, construction levels, and less critical alignment and position sensing devices.
If you need a collimated beam with smaller dimensions, consider using the 300-0380-780 lens or, the LDM 4500 KIT. For example... when used with the Hitachi HL6312G (635nm/5mW) laser diode, a collimated beam measures approximately 0.715 mm in the parallel axis by 2.85 mm in the perpendicular axis, with divergence angles of 1.2 mrad x 0.34 mrad respectively. (The figures mentioned may vary from one diode to another or, with other manufacturers diodes).
The plastic lenses are available unmounted or in a convenient aluminum mount with a .375-64 external thread. The extra-fine pitch thread allows precise adjustment of the lens when collimating or focusing the beam.
|Part Number (thread mount)||302-0380-780||302-0395-780|
|Unit price (Qty 1-49)||$14.15||
|Description||Injection Molded Plastic Aspheric Lens, with 3/8-64 Threaded Mount|
|Optical Specifications||Basic optical specifications as listed in the following section|
(diameter x length)
|3/8-64 thread x 5.9 mm||3/8-64 thread x 3.8 mm|
|Part Number (unmounted lens)||300-0380-780||300-0395-780|
|Unit price (Qty 1-49)||$4.70||$4.20|
|Description||Injection Molded Plastic Aspheric Lens, unmounted|
|Design Wavelength||780 nm|
|Focal Length||3.40 mm||16 mm|
|Working/Source Distance||1.43 mm||13.79 mm|
|Clear Aperture||3.20 mm||4.60 mm|
|Field Size (diameter) *||0.150 mm||0.559 mm|
|AR Coating, MgF2||780 nm|
|Transmission||> 95%||> 97%|
|Cover Glass Thickness||1.25 mm|
|Cover Glass Index (n)||1.55||1.51|
|Temperature Range||Storage Temperature -30 ~ +75
Working Temperature -10 ~ +65 °C
(diameter x length)
|Ø5.0 x 2.11 mm||Ø6.5 x 2.33 mm|
* The Field Diameter of a collimating lens defines the largest size emitter the lens will accommodate and still maintain other optical specifications, such as the wavefront aberration specification.
Example: If the field diameter specification is 100 microns, then the size of the laser diode emitter must be less than 100 microns in either axis. Generally, when using lower powered diodes (1mW to 100mW) the emitter size is not a concern, as the emitter is typically only a few microns in the perpendicular or parallel axis. When using higher power diodes, diodes arrays, or LED’s the emitter can be significantly larger – emitters larger than 100 microns are common.
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