Low divergence optics

[steve001]

Purchase a lens with a focal length of -6mm, that is generally the lowest and easyist to find off the shelf lens you can buy.

 

[stevetexas]

The beam specs are now variable.  I can remove the beam expander for the original beam profile (approx 1.4 mRad divergence)  Or add the beam expander and have a variable beam.  
None of this requires modding the Aries    

I am using a Melles-Griot 09 LBZ 001  3x Beam expander (specs/link in next reply)

 

[stevetexas]

http://shop.mellesgriot.com/product...BZ 001&plga=011088&mscssid=&From=GlobalSearch

General Characteristics
Expansion Ratio: 3×
Wavelength Range: 415–700 nm
Minimum Focus Distance: 1.5 m
Laser Type: Ion and YAG
Wavefront Distortion: <[ch955]/4 (p-p) at 632.8 nm
Input Aperture: 7.32 mm
Maximum Input Beam Dimension (1/e2): 4.83 mm
Exit Aperture: 22.0 mm
Coating: HEBBAR™ /078
Mounting: 1-inch–32 TPI female
1-inch–32 TPI male with included C-mount adaptor
Housing Material: Black-anodized aluminum
Damage Threshold (cw): 70 kW/cm2
Damage Threshold (pulsed): 3.8 J/cm2 in 13 ns

Extended Description Details at Melles Griot_09LBZ001.pdf

 

[stevetexas]

According to Pseudo's divergence claculator, here is how the beam profile is affected:
http://www.pseudonomen.com/lasers/calculators/mRadCalculator.html

Original stock Aries: 1mm at aperature, 90 mm at 215 Ft = 1.36 mRAD = 1.4 mRad
With beam expander: 4mm at aperature, 50 mm at 215 Ft = 0.70 mRAD

The tradeoff is larger initial beam diameter - this means less burning power. However, now the beam is still small enough to be entirely contained within a normal magnifying glass at 200 ft.

I'll try to get a 200 foot match light...

 

[Daedal]

That is VERY impressive!! I am very glad this worked out for you It looks very nice. Let's see that burn... I'm excited about it

GL;
DDL

 

[stevetexas]

DDL - here you go... Burning at 215 feet

http://www.laserpointerforums.com/forums/YaBB.pl?num=1185079181