SMA is often used for RF/MW circuitry, which is generally completely out of the scope of Arduino
interfacing, its unusual to see a sensor with an SMA connector that is not RF/microwave. Get a female
bulkhead connector and solder wires to it? (Assuming its standard SMA, not reversed, both types exist).
[ BTW SMA connectors are rated to 18 GHz, and would used on communications laser receivers
because of high bandwidth used for such detectors - I presume you don't need such bandwidth! ]