The only engraving on the bulb I can see says "NRJ8EE" but Google searching that brings up nothing.
Also, if we can't identify the bulb, is anyone able to tell if the fixture would be able to support an LED bulb with the same base?
As has already been stated High Intensity Discharge lamps only use a specific bulb and as the name implies, is energized under high voltage. Unless a new type of bulb is labeled for this type of lamp it would be wise to use an exact replacement bulb. I've noticed that LED lights have become increasingly more powerful (brighter) and inexpensive the past few years. If energy conservation (or frugality) is a priority it might be worth investigating if the present high energy using lamps should be replaced with the cooler emitting LED's. Here is a link you may find helpful, to one such lamp: http://www.amazon.com/gp/product/B00DJPMD3K?keywords=security%20LED&qid=1443644066&ref_=sr_1_14&sr=8-14