MONOCHROMIA

I have put together a presentation on some data I generated with my new Spectrophotometer. I will discuss this in our PFG IG Live on 8 MAY 2022. Here is a link to the presentation, please read beforehand.

Monochromic Light Sources

Bits and Pieces:

UV Germicidal Lamp (use caution!) from McMaster-Carr, to fit PortaTrace 1012 (T5, 8W): 9188K12
(“…germicidal lamps emit high-intensity UV radiation that can cause sunburn and conjunctivitis. The skin and eyes must therefore not be exposed to direct or reflected unfiltered radiation.”)

Flexible Thin Film UV Filters from Edmund Optics #39-426

Possibly same UV filter material from McMaster-Carr: 7769T5
”The material allows less than 10% transmission below 390 nanometers.”

Green filter from McMaster (7769T3) “Green filters allow less than 10% transmission between 380 and 480 nanometers and between 540 and 670 nanometers.” (Helium’s main line is 587nm) See Below…

The main line (non-UV) from Germicidal bulbs appears to be about 540 and a secondary line at 590.

ROSCO filter selector

ROSCO filter R90 (what Adam B. selected):

ROSCO filter R139 (I think this may be slightly better for the germicidal bulb):

The McMaster-Carr Green Filter part number 7769T3 is the Roscolux R91 Primary Green. (confirmed via email)

Spencer’s pile of links (@spencer_webb_nh):

Atomic Spectra (gsu.edu)

Spectra of Gas Discharges

ASEQ Instruments - spectrophotometers

ROSCO color filters

Cheap Lasers as Monochromatic light sources - Pierre’s Garage

Edmund Optics — Main page.

Edmund Optics — How Optical Flats Work

Reading Light Bands - Kemet

Spencer’s Posts on IG:

eBay purchase of monochromatic light source

monochromatic light source arrived

refurbishing the Lapmaster

First Light from the Lapmaster

A Cheeeeep spectrometer (see also Amazon to purchase here.)

Cheeeeep spectrometer improvement and proof of helium

Proving optical flats

The PFG IG Live with Adam B.

showing grinding artifacts with the optical flat

From John Grimsmo (@johngrimsmoknives):

I bought the germicidal bulbs and the triphosphor ones, tried them both, yet didn't see enough benefit from using the scary ones so I've got the regular ones in now. I do wish the fringes were brighter and crisper. I see your guys posts with sodium or helium and they're MUCH brighter. Mine are green from the filter paper and just not always super visible. It does work well though!