A method is disclosed for irradiating a biological sample with far infrared (FIR) irradiation, including providing tunable FIR irradiation, removing X rays from the irradiation, and irradiating at least one biological sample with the tunable FIR irradiation, wherein at least a component of the biological sample undergoes at least one of a conformational change or a phase change in response to the irradiating. An FIR irradiation device is disclosed, including an FIR source producing an FIR irradiation having a tunable wavelength, the source being capable of continuous-wave output, and a filter receiving the irradiation from the source.