I have an underwater green unit (like this Underwater Scuba & Dive Green Laser Pointer ) that i have had for a number of years.
I got it out to prepare for an upcoming SCUBA trip and noticed the projected dot, "grows a tail", like classical pictures of an astronomical comet, after turn-on. The "tail" is rougly triangle shaped, with one side arcing and brighter, and covering mabye 15-20 degrees of arc about the center dot. It is always oriented at the same angle wrt an arbitrary point on the circle. There are some other, much dimmer, narrow spikes (not triangles) visible as well, one being 180 degrees from the "comet tail." These spikes also dont appear, or are even dimmer, on initial turn-on. If the unit hasnt been on for a long time, it takes the tail and spikes several seconds to "grow". If it is turned off and immediately turned on, it takes only one or two seconds to "grow". I changed batteries and same result. I had not noticed it doing this until recently.
The regulator board has what looks like a minature potentiometer. I havent adjusted it. I am an electronics engineer but have no experience with lasers.
What is the phenomena I am seeing? Can i fix or improve it?
I got it out to prepare for an upcoming SCUBA trip and noticed the projected dot, "grows a tail", like classical pictures of an astronomical comet, after turn-on. The "tail" is rougly triangle shaped, with one side arcing and brighter, and covering mabye 15-20 degrees of arc about the center dot. It is always oriented at the same angle wrt an arbitrary point on the circle. There are some other, much dimmer, narrow spikes (not triangles) visible as well, one being 180 degrees from the "comet tail." These spikes also dont appear, or are even dimmer, on initial turn-on. If the unit hasnt been on for a long time, it takes the tail and spikes several seconds to "grow". If it is turned off and immediately turned on, it takes only one or two seconds to "grow". I changed batteries and same result. I had not noticed it doing this until recently.
The regulator board has what looks like a minature potentiometer. I havent adjusted it. I am an electronics engineer but have no experience with lasers.
What is the phenomena I am seeing? Can i fix or improve it?