RESUMO
We report on two ultrastable lasers each stabilized to independent silicon Fabry-Pérot cavities operated at 124 K. The fractional frequency instability of each laser is completely determined by the fundamental thermal Brownian noise of the mirror coatings with a flicker noise floor of 4×10^{-17} for integration times between 0.8 s and a few tens of seconds. We rigorously treat the notorious divergences encountered with the associated flicker frequency noise and derive methods to relate this noise to observable and practically relevant linewidths and coherence times. The individual laser linewidth obtained from the phase noise spectrum or the direct beat note between the two lasers can be as small as 5 mHz at 194 THz. From the measured phase evolution between the two laser fields we derive usable phase coherence times for different applications of 11 to 55 s.
RESUMO
Facial aesthetics involve basic artistic principles that relate individual features to the face as a whole. These principles, such as balance and proportion, are key elements in the development of hair restoration surgery and can be applied to reconstructive procedures for the trauma or burn patient. This paper describes the application of anthropometric and artistic principles used in hair reconstruction. Attention has been directed to the procedures used to determine hairline contour and placement, and certain aspects of frontotemporal recession management. The frontal hair has a profound effect on facial balance because of the major role hair plays in framing and visually enhancing the face. The presence of frontal hair and facial framing also serves to retain a vital element of autonomy in appearance for the individual.
