mode hopping

[xirrious]

I have a HL-532-300 from laserBTB. It seems to mode hop alot and when I first turn it on it'll shine bright before dimming a bit where it's easily noticeable. When it's cold cold it needs to warm up real quick before coming to full power and then drops down again. However it drops from high to low power quicker with warmer temperatures. Is this a flaw ? Or is this a characeristic of dpss lasers? If the latter can someone intelligent explain WHY my laser mode hops and why it's based on temperature? Any insight would be great. Thanks LPF members!

 

[ultimatekaiser]

mode hopping is common in DPSS, especially small handhelds. A lot of things can cause it, but high temperature is usually a common component. its possible the alignment just isn't perfect, but there are a huge handful of factors involved...temperature of each individual component, the type and style of heat sinking, type of diode and its own mounting, mirror surfaces (usually coatings on the crystals in handhelds), power instability from the battery, and more. generally it should be TEM00 the majority of the time though, or very close. if it hops excessively it's generally considered a bug, but its normal.

I wouldn't be suprised if the alignment was ever so slightly off. fractions of a mm count, and virtually anything could throw it off, such as a badly placed speck of dust.

 

[IsaacT]

What ultimatekaiser said. The fact that your laser dims quickly after turning it on and that the mode hopes are "easily" noticeable is what worries me. For modes to be very easy to see in that powerful of a 532nm laser means it must be dimming quite a bit. It sounds like maybe it is because the host is the HL version. I imagine a PL version would be more stable. If I were you I would try to sell it to someone and recup some losses and then buy a better one. But I am unrealistically critical of my lasers.

 

[xirrious]

Yeah maybe that's why it was sold to me in the first place. It is impossible to tell but if it ran at 400mw I'd say it was dropping in power by 100mw during mode changes. I still may get a 589 before a powerful 532 but now I have a decision. Thanks to both of you for solid advice.