Support Map Order Equip. We believe a very convincing case is made here that these objections to lasers are invalid - that searches for ETI signals are far more likely to be successful in the optical spectrum. The microwave objections to the optical approach are listed below. Finally, at the bottom of this page we state the one reason why lasers are vastly superior to microwaves for interstellar communications. This one reason alone should have been sufficient to have caused the main thrust of SETI researchers to be in the optical regime.
Uplink gain has to be limited at optical wavelengths.
Argument 1 Photon noise much higher than thermal noise at optical wavlengths. Argument 2 Backround noise from ETIs' star is much higher at optical wavelengths. An all-sky survey not possible at optical wavelengths. Argument 4 Technology for ETIs more expensive at optical wavelengths. Argument 5 Lack of magic frequencies at optical wavelengths.