a. A He-Ne laser producing all of its light at 633 nm is a non thermal light source. This is because unlike thermal radiation sources that emit their radiation over a broad range of wavelengths (frequencies), He-Ne laser is a low energy that only produces its non thermal radiation in a narrow banc of 633 nm.
No, it is not possible to have an electromagnetic wave with a large radiance and zero irradiance. This is particularly because an illuminance can only include less energy per every unit area but not more than irradiance.
A black light (also known as a UV-A light) is a kind of lamp which only emits long wave ultraviolet light. Although ultraviolet light is not visible, black lights make objects glow by also emitting a violet light which allow people to see objects (Kitsinelis