Measurement of Radio-Frequency Radiation Pressure

We perform measurements of the radiation pressure of a radio-frequency (RF) electromagnetic field which may lead to a new SI-traceable power calibration. There are several groups around the world investigating methods to perform more direct SI traceable measurement of RF power (where RF is defined to range from 100s of MHz to THz). A measurement of radiation pressure offers the possibility for a power measure traceable to the kilogram and to Planck's constant through the redefined SI. Towards this goal, we demonstrate the ability to measure the radiation pressure/force carried in a field at 15~GHz.Comment: 2 pages 4 figure

Feedback Control of a Nonlinear Electrostatic Force Transducer

We document a feedback controller design for a nonlinear electrostatic transducer that exhibits a strong unloaded resonance. Challenging features of this type of transducer include the presence of multiple fixed points (some of which are unstable), nonlinear force-to-deflection transfer, effective spring-constant softening due to electrostatic loading and associated resonance frequency shift. Furthermore, due to the utilization of lowpass filters in the electronic readout circuitry, a significant amount of transport delay is introduced in the feedback loop. To stabilize this electro-mechanical system, we employ an active disturbance-rejecting controller with nonlinear force mapping and delay synchronization. As demonstrated by numerical simulations, the combination of these three control techniques stabilizes the system over a wide range of electrode deflections. The proposed controller shows good setpoint tracking and disturbance rejection, and improved settling time, compared to the sensor alone

Towards the generation and fiber-link transfer of ultra-stable 895 nm signal for characterization of a microcell-stabilized laser

International audienceWe report on the in-progress implementation and characterization of an optical setup aiming to generate an ultrastable 895 nm signal, referenced to a cavity-stabilized laser, and to transfer it through a 30-m compensated fiber-link to a neighboring lab. This 895 nm signal will be used as a stable reference for the characterization of an external-cavity diode laser stabilized onto a Cs vapor micro-fabricated cell using dualfrequency sub-Doppler spectroscopy

In-progress study of microcell-stabilized lasers using dual-frequency sub-Doppler spectroscopy

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Supplementary document for Synthetic FM triplet for AM-free precision laser stabilization and spectroscopy - 6745536.pdf

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Cs microcell optical reference with frequency stability in the low 10−13 range at 1 s

International audienceWe describe a high-performance optical frequency reference based on dual-frequency sub-Doppler spectroscopy (DFSDS) using a Cs vapor microfabricated cell and an external-cavity diode laser at 895 nm. Measured against a reference optical signal extracted from a cavity-stabilized laser, the microcell-stabilized laser demonstrates an instability of 3 × 10−13 at 1 s, in agreement with a phase noise of +40 dBrad2/Hz at 1-Hz offset frequency, and below 5 × 10−14 at 102 s. The laser short-term stability limit is in good agreement with the intermodulation effect from the laser frequency noise. These results suggest that DFSDS is a valuable approach for the development of ultra-stable microcell-based optical standards

A New Generation of NIST Laser Power Standards Using Microfabrication Techniques and Carbon Nanotubes

The NIST Sources and Detectors group is developing a new family of chip-scale laser power standards that are fast, compact, and robust. By combining state-of-the-art micro-fabrication techniques with vertically aligned carbon nanotube (VACNTs) as absorbers, these new standards promise accuracy with an unprecedented capability for portability and use outside of standards laboratories, including for space-based applications. While the focus of this effort is to develop standards for laser power measurements, the design and construction is also being applied to incoherent radiation. The development of both cryogenic and room temperature devices for powers from tens of microwatts to 100 milliwatts and wavelengths from visible to THz will be described with particular attention to the performance of room temperature devices for visible wavelengths