I am trying to set up a Raman spectroscopy experiment at home using a 50mW 532nm laser. This qualifies as a class 3B laser, so even very brief accidental reflections of the laser beam off of glassy objects (or perhaps even a white painted wall?) can cause eye damage.

I have purchased two sets of protective eyeglasses that both claim to block out a wavelength range that includes 532nm, but one was USD \$42.000 while the other was like USD \$10.00. I can't tell from the product descriptions why one is 4x as expensive as the other.

So, I turn to you PSE, for some thoughts on why such a big price difference? Would you trust a pair of \$10.00 glasses to protect your eyes from a 50mW laser?


Here are the parameter specs copied and pasted from ebay:

Expensive pair

Protection bands nm: 190-540nm and 900-1700nm

Optical density: OD = 4-5

Suitalbe for Laser and Wavelength

Quadrupled Nd: YAG laser 266nm OD = 5

An Ar ion laser 488-514.5nm OD = 5

Excimer laser He-Cd 441.6nm OD = 5

Harmonic Nd: YAG laser 532nm OD = 4

Ion laser 514nm OD = 5

YAG laser 1064nm OD = 5

Semi-conductor laser (diode laser) 980,1510,1530,1610 nm OD = 5


Cheap pair

Protection wavelength range:532nm

Protection features:all-round absorption

Visible light transmittance:>55%

Optical Density:> 5.0, (OD +4, OD +5)

Attenuation:(10-6 <N% <10-4)

  • 2
    $\begingroup$ I spent my whole career, over four decades, working with lasers of various types and powers. Pay the money for the good ones. Eyes are not replaceable. $\endgroup$
    – Ed V
    Commented Nov 27, 2022 at 15:25
  • 1
    $\begingroup$ @EdV that is a fair comment but does not answer the question that is about physics and not about whether it is worth paying 30 bucks more or not. $\endgroup$
    – hyportnex
    Commented Nov 27, 2022 at 15:36
  • $\begingroup$ @hyportnex So what is the OP going to do to determine the filter composition and quality? I have seen plastic laser protection goggles melted by very brief exposure to the 514.5 nm argon laser line. And a glass filter simply shattered when exposed to the same couple of watts at 514.5 nm. So aside from checking the specs of the two goggles, what else can reasonably be done and how is a true physics answer feasible? I would buy two at $42 each, put one on and carefully test the other pair, not directly on-center with either eyepiece, and see what gets transmitted. $\endgroup$
    – Ed V
    Commented Nov 27, 2022 at 15:40
  • 1
    $\begingroup$ Things like weight, anti-fog, comfort, and style (at least for some) all come into play, particularly if you wear them all day long. $\endgroup$
    – Jon Custer
    Commented Nov 27, 2022 at 15:55
  • $\begingroup$ The obvious difference is the expensive pair gives you a lot more information about OD (and has probably been tested and certified) at a wider range of optical wavelengths. That "explosion-proof" line probably also adds a bit to the cost. (And frankly $40 is still pretty cheap, I wouldn't be surprised if other safety glasses go up to 10x that) $\endgroup$
    – The Photon
    Commented Nov 27, 2022 at 16:23

1 Answer 1


Things that could be different, while having the same OD at the same wavelength, include:

  • Spot power handling capability
  • Mechanical ruggedness
  • $\begingroup$ I see a lot of eyewear specs refer to YAG lasers. I'm using a diode laser. Does this make a difference in the level of protection I need? $\endgroup$
    – ben
    Commented Nov 27, 2022 at 17:46
  • 1
    $\begingroup$ @ben no, the power and collimation does. at several W per um², a laser would just burn through your glasses.. $\endgroup$
    – tobalt
    Commented Nov 27, 2022 at 17:50
  • 1
    $\begingroup$ Another one is transmissivity for wavelengths outside the stop band(s). $\endgroup$
    – The Photon
    Commented Nov 27, 2022 at 23:04

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