A Blu-ray violet laser is made up into a hand held unit.
“Continue reading” for more details and photos.
This is available new for US$40 (cost about AU$65 inc postage from eBay) as a PS3 Blu-ray laser replacement part (KES-400AAA) which includes the carriage and lots of complicated high tech optics. The violet laser also has red and infrared lasers in the same package. Remarkably cheap really. Plenty of eBay sellers for this if you search for the part number.
Leslie Wright (Plazmatron on 4HV) seems to be one of the early people to do this and has an excellent segment on his site in conjunction with Sam from SAM’s laser FAQ. By and large I have followed his construction and used the same constant current supply. I first saw it on Mikes Electric stuff.
The beam in fog (from my fog machine), aiming up towards the camera. Short wavelengths scatter better (ie the sky is blue!). On a 2 second exposure it is enough to saturate the camera.
I took a lot of care to do the initial soldering of the laser while in circuit including the 0.1 uF cap across the diode (shorted and also the iron was earthed to the case). The flexible plastic circuit strip was cut and I removed other shorts and ran from low current with the described LM317LZ constant current supply starting with 10 mA. The red laser is speckled (i.e. lasing) and appears to be several mW.
The violet laser, however was far less bright than the red one and less speckled. Part of this is due to the eye’s reduced sensitivity at this 405 nm wavelength. It still fluoresces things, particularly paper. Ith (threshold current) was about 26 mA judged by increased brightness but hard to be sure.
The unfocussed beam seems complete unlike the example of a damaged beam. I have run the current briefly (later up to a momentary peak of 79 mA without a change in beam).
The top photo shows the optics side with cover removed. The laser diode is the small assembly at the extreme left with the red mark on it. The middle photo shows the other side with the objective lens and voice coil positioning. It is 7.5 cm (3 inches) across. The bottom photo shows the 5 pins of the laser diode for the 3 lasers and photodiode.
The red laser used or DVD compatibility is turned on. Note the yellow 0.1 uF caps epoxied to the heat sink which I added to provide the electrostatic discharge (ESD) protection and a stable base for the wires to the driver. I eventually added three of these, one for each diode. The red beam exits the objective lens on the other side. It is a complicated beam having passed through various diffraction gratings and lenses like Fresnel lenses. The bottom photo shows the beam projected through translucent plastic a few inches away.
The Blu-ray violet laser lighting up the optics. The diode is projecting onto a piece of paper which is fluorescing. It is a very broad beam direct from the photodiode and not at all laser like. Safe to look at in this state only but not in the focused set-up. The bottom photo shows the violet objective beam with the various lines and circles as with the red laser.
The constant current supply is set at around 30 mA and the violet laser collimated into a spot. Here it shines onto paper and fluoresces a bright blue.
Thee tip of a fluorescent marker pen.
Rhodamine gives intense orange fluorescence.
The laser was made up in a metal case. Ironically it used to contain a pen/red laser pointer. It shows the switch for selecting red/IR/violet. I wasn’t really thinking because I should have had some low value resistors in the lines or some extra current shunting as I have damaged the red and possibly the IR diodes from over voltage or current. It is a nicely weighted comfortable unit.
The sabre like beam highlighted by fog. Pointing up to the camera the brightness is higher. The longer photo exposure and heavy fog makes these look brighter than they are.
The dog was very interested in the BluRay violet laser dot (at first).
A heart shaped hologram (from a cheap laser pointer) showing the bright blue fluorescence from paper.
The heart hologram modelled by Mandy. Works great on white tee shirts and the hologram is low powered enough to be safe in public.
The beam against my fluoro cycling shirt with brilliant yellow green fluorescence highlighted by fog. Above that, the same pattern through a uranium marble with bright green fluorescence.
Related pages
Fluorescence in fluidsTry something else
FlamethrowersExternal links
Photo Date: 2008