The number of bits of information that can be obtained from a single unmodulated wavelength of light is related to the concept of channel capacity in information theory.
In the context of digital communication, the Shannon-Hartley theorem provides a theoretical limit on the maximum achievable data rate (in bits per second) for a given channel bandwidth and signal-to-noise ratio. The formula for channel capacity is:
C = B * log2(1 + S/N)
Where: C is the channel capacity in bits per second B is the bandwidth of the channel in hertz S is the signal power N is the noise power
For a single unmodulated wavelength of light, the bandwidth B would be zero since there is no modulation or variation in the signal. Therefore, the channel capacity in bits per second would also be zero.
However, it's worth noting that this calculation assumes a continuous signal. In practical scenarios, modulation techniques such as amplitude modulation, frequency modulation, or phase modulation are typically employed to transmit information using light waves. These modulation techniques introduce variations in the amplitude, frequency, or phase of the light wave, allowing for encoding and transmission of data. In such cases, the number of bits that can be transmitted per wavelength of light would depend on the modulation scheme, encoding technique, and other factors.