This approach avoids modulating the laser at different frequencies (pulsed or modulation) and effectively presents a platform for lifetime detection that could more practically be implemented on any standard flow cytometer.
Intensity and phase shift with respect to a reference signal of backscattered radiation are measured by means of the same lock-in amplifier used to modulate the laser beam.
In order to overcome the typical drawbacks of a conventional Fabry-Pérot interferometer, i.e. low sensitivity sensing spots at the interference extrema and the ambiguity of the displacement direction, the interferometer modulates the laser wavelength (about ±10−3 wavelengths) periodically with a frequency of 12.5 MHz.
Raman Khanna, managing director of Diamondhead Ventures, asked Goodman for a consultation the other day on a plan to invest $4 million in a new technique to modulate the laser waves that transmit data down a fiber strand-at one-tenth the cost of current technology.
Alternatively, precise phase shifts can be introduced by modulating the laser frequency.
By modulating the laser beam divergence we were able to induce precise axial shifts of the focal spot.
Modulating the laser power, repetition frequency, and duty cycle (fraction of time on) allowed us to tune the peak temperature and extent of spatial heating.
Quasi-DC photocurrent imaging was initially performed by modulating the laser excitation (∼100 200 Hz) using a mechanical chopper and current was detected using a lock-in amplifier.
With respect to the patient's physical condition, the use of reinforcing and reducing acupuncture information to modulate the laser beam, which adheres to the principles of TCM dialectical therapy, follows the TCM acupuncture principle of treating deficiency syndrome.
Besides using frequency division multiplexed (FDM) analog transmission of multiple carriers, it is possible to use digital (binary or on/off) modulation of lasers, which means modulating the lasers with a time division multiplexed baseband digital signal.
