Abstract: In a general aspect, a method is presented for increasing the measurement precision of an optical instrument. The method includes determining, based on optical data and environmental data, a measured value of an optical property measured by the optical instrument. The optical instrument includes an optical path and a sensor configured to measure an environmental parameter. The method also includes determining a predicted value of the optical property based on a model representing time evolution of the optical instrument. The method additionally includes calculating an effective value of the optical property based on the measured value, the predicted value, and a Kalman gain. The Kalman gain is based on respective uncertainties in the measured and predicted values and defines a relative weighting of the measured and predicted values in the effective value.

Abstract: In a general aspect, a method is presented for increasing the measurement precision of an optical instrument. The method includes determining, based on optical data and environmental data, a measured value of an optical property measured by the optical instrument. The optical instrument includes an optical path and a sensor configured to measure an environmental parameter. The method also includes determining a predicted value of the optical property based on a model representing time evolution of the optical instrument. The method additionally includes calculating an effective value of the optical property based on the measured value, the predicted value, and a Kalman gain. The Kalman gain is based on respective uncertainties in the measured and predicted values and defines a relative weighting of the measured and predicted values in the effective value.

Abstract: A catheter includes a proximal shaft, a distal shaft, a pressure sensor, and at least one pressure sensor wire. The proximal shaft is substantially C-shaped such that in cross-section, the proximal shaft includes a first circumferential end, a second circumferential end, and a gap between the first circumferential and circumferential end. The proximal shaft defines a groove configured to receive a guidewire therein. The distal shaft is coupled to the proximal shaft and defines a guidewire lumen therein. The pressure sensor is coupled to the distal shaft. The pressure sensor wire is operably connected to the pressure sensor. A proximal portion of the pressure sensor wire is disposed within a proximal shaft wall of the proximal shaft and a distal portion of the pressure sensor wire is disposed within a distal shaft wall of the distal shaft.

Abstract: In a general aspect, a device is disclosed for providing a reference frequency of light. The device includes a housing having a first opening and a second opening. A first optical window covers the first opening and is coupled to the housing by a first ceramic bond that forms a hermetic seal around the first opening. A second optical window covers the second opening and is coupled to the housing by a second ceramic bond that forms a hermetic seal around the second opening. The device also includes an etalon disposed within an evacuated volume enclosed by at least the housing, the first optical window, and the second optical window. The device additionally includes one or more supports suspending the etalon in the evacuated volume. The one or more supports are formed of a material having a thermal conductivity no greater than 5 W/m·K at room temperature.

Abstract: In a general aspect, a wavelength of light is measured. In some aspects, a wavelength measurement system includes an interferometer, a camera system, a sensor and a control system. The interferometer includes two reflective surfaces and a transmission medium between the two reflective surfaces. The interferometer is configured to receive an optical signal from a laser and produce an interferogram in response. The camera system is configured to receive the interferogram from the interferometer and generate interferogram data in response. The interferogram data represents the interferogram received from the interferometer. The sensor is configured to sense an environmental parameter of the transmission medium and generate sensor data in response. The control system is configured to perform operations including, receiving the interferogram data from the camera system and the sensor data from the sensor; and computing a wavelength of the laser based on the interferogram data and the sensor data.

Abstract: In a general aspect, an imaging method is presented that includes receiving, at a vapor-cell sensor, input optical signals and electromagnetic radiation from at least a test device to generate an output optical signal. The output optical signal is processed at a single pixel camera to generate camera output data. An image of the electromagnetic radiation is constructed by operation of a computer system based on the camera output data. In some implementations, the single pixel camera includes a patterned light generator and a photodetector. In these implementations, the imaging method includes receiving, at the photodetector, patterned instances of the output optical signal generated by the patterned light generator. Each patterned instance represents a respective portion of the image of the electromagnetic radiation. Moreover, the intensity of each patterned instance may be measured, by operation of at least the photodetector, to generate the camera output data.

Abstract: A catheter includes a proximal shaft, a distal shaft, a pressure sensor, and at least one pressure sensor wire. The proximal shaft is substantially C-shaped such that in cross-section, the proximal shaft includes a first circumferential end, a second circumferential end, and a gap between the first circumferential and circumferential end. The proximal shaft defines a groove configured to receive a guidewire therein. The distal shaft is coupled to the proximal shaft and defines a guidewire lumen therein. The pressure sensor is coupled to the distal shaft. The pressure sensor wire is operably connected to the pressure sensor. A proximal portion of the pressure sensor wire is disposed within a proximal shaft wall of the proximal shaft and a distal portion of the pressure sensor wire is disposed within a distal shaft wall of the distal shaft.

Abstract: Neuromodulation devices for delivering neuromodulation therapy to distal vascular portions and proximal vascular portions and associated systems and methods. A neuromodulation device can include an elongated shaft having a proximal portion and a distal portion, each portion being sized and shaped for simultaneous positioning and deployment within respective proximal and distal vascular portions of a human vasculature. The elongated shaft can have an outer cross-sectional dimension that decrementally changes towards the distal end. The elongated shaft can also have a plurality of sections, each section configured to be independently shaped upon deployment in the intended distal or proximal vascular portion.