User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2009/02/22/Optical tweezers/Spatial filtering
To get rid of higher order modes in a laser beam, one needs to filter the higher orders out of the beam. To do this, we can use either a single mode fiber that only allows the TEM00 mode to propagate through it, or we can use a spatial filter. I have a design for a spatial filter and the parts list can be found below.
I am a fan of spatial filters because they are cheaper than single mode fiber launches and because the optomechanics you use for them can be harvested for other uses if you don't need it anymore. As Alton Brown would say, a single mode fiber launch is a uni-tasker and the only uni-tasker I want in my kitchen is the fire extinguisher.
Unfortunately both a spatial filter and a fiber launch have advantages and disadvantages over each other. If anyone reading this is on the fence about purchasing one, then I'd suggest a pro/con list for your setup.
|Component||Model Number||Cost||# Needed||CAD Drawing||Sketchup|
|Mounting Base, 1" x 2.3" x 3/8"||BA1S||$5.13||1||Yes||Yes|
|Translating TR Post 2" to 2 1/4"||TRT2||$49.50||1||Yes||Yes|
|Post Holder with Spring-Loaded Thumbscrew, L=3"||PH3-ST||$8.27||1||Yes||Yes|
|SM1 Series Z Translator||SM1Z||$175.40||1||Yes||Yes|
|SM1 to 9mm Lens Cell Adapter||S1TM09||$20.10||1||Yes||Yes|
|30 mm Cage Plate Adapter||CP02B||$13.70||1||Yes||Yes|
|30 mm Cage Assembly, XY Translating Lens Mount||HPT1||$161.00||1||Yes||Yes|
|Ø10 µm Mounted Pinhole||P10S||$59.30||1||Yes||Yes|
|SM1 Threaded 30 mm Cage Plate||CP02||$15.63||1||Yes||Yes|
|SM1 Lens Tube, 0.5" Long||SM1L05||$12.59||1||Yes||Yes|