Please tell me about the effects that a sheet of paper and a pane of glass can have on DSSS, FHSS, Diffused Infrared, and LASER, when held in front of transiting/receiving device.
At 2.4 GHz, radio waves encounter obstacle-induced signal loss of about 3 dB for glass windows and 5 dB for windows with metallic tint. Both DSSS and FHSS use RF, but DSSS can recover from partial signal loss better than FHSS.
Lasers require strict line of sight and cannot penetrate solid objects. A laser modem can be directed through a transparent window, so long as the glass is not tinted with reflective material.
Diffused Infrared bounces off surfaces to get around opaque objects. If you held an object in front of a diffused IR transmitter, signal could still bounce off walls to reach a receiver in the same room. However, diffused IR generally cannot leave a closed room. IR is degraded by glass, depending upon thickness and impurities. As a result, diffused IR is largely stopped by exterior windows.
I have not seen any research concerning RF or infrared attenuation by a sheet of paper. But if I had to guess, I would speculate that ordinary paper is more opaque to light than absorbent to radio waves.