We have constructed several impedance-matched low-pass filters using a stripline geometry with a ... more We have constructed several impedance-matched low-pass filters using a stripline geometry with a dissipative dielectric. The filters are compact, simple to construct, and operate in cryogenic environments. The dissipative dielectric consists of magnetically-loaded silicone or epoxy, which are commercially available under the trade name Eccosorb. For a stripline length of 32 mm, the filters have a passband that extends from dc to a 3 dB bandwidth between 0.3 and 0.8 GHz. The 3 dB bandwidth can be adjusted beyond this range by changing the filter length. An extremely broad stopband at higher frequencies, with attenuation exceeding 100 dB, is achieved along with a return loss greater than 10 dB measured up to 40 GHz. This combination of high attenuation and low reflected power across a broad stopband ensures that spurious or unwanted signals outside the passband do not reach or return to the device under test. This type of filter has applications in microwave frequency measurements of ...
This article reviews the state of rapidly emerging terahertz hot-electron nanobolometers (nano-HE... more This article reviews the state of rapidly emerging terahertz hot-electron nanobolometers (nano-HEB), which are currently among of the most sensitive radiation power detectors at submillimeter wavelengths. With the achieved noise equivalent power close to 10^-19 W/Hz^1/2 and potentially capable of approaching NEP 10^-20 W/Hz^1/2, nano-HEBs are very important for future space astrophysics platforms with ultralow submillimeter radiation background. The ability of these sensors to detect single low-energy photons opens interesting possibilities for quantum calorimetry in the mid-infrared and even in the farinfrared parts of the electromagnetic spectrum. We discuss the competition in the field of ultrasensitive detectors, the physics and technology of nano-HEBs, recent experimental results, and perspectives for future development.
For high critical current density (J_c), a type-II superconductor must have defects or inclusions... more For high critical current density (J_c), a type-II superconductor must have defects or inclusions which pin the vortex lattice. A bundle and cold-draw process is used to produce superconducting wire with micron-sized NbTi filaments which have a nanometer-sized array of ferromagnetic pins. The wire with the highest Jc has a pin diameter of 4 nm and a pin spacing of
We investigate the single photon detection and reset mechanisms in superconducting nanowires, whi... more We investigate the single photon detection and reset mechanisms in superconducting nanowires, which have received recent, widespread attention for use in applications requiring fast optical and near infrared photon counting. These devices are fabricated from ...
We have constructed several impedance-matched low-pass filters using a stripline geometry with a ... more We have constructed several impedance-matched low-pass filters using a stripline geometry with a dissipative dielectric. The filters are compact, simple to construct, and operate in cryogenic environments. The dissipative dielectric consists of magnetically-loaded silicone or epoxy, which are commercially available under the trade name Eccosorb. For a stripline length of 32 mm, the filters have a passband that extends from dc to a 3 dB bandwidth between 0.3 and 0.8 GHz. The 3 dB bandwidth can be adjusted beyond this range by changing the filter length. An extremely broad stopband at higher frequencies, with attenuation exceeding 100 dB, is achieved along with a return loss greater than 10 dB measured up to 40 GHz. This combination of high attenuation and low reflected power across a broad stopband ensures that spurious or unwanted signals outside the passband do not reach or return to the device under test. This type of filter has applications in microwave frequency measurements of ...
This article reviews the state of rapidly emerging terahertz hot-electron nanobolometers (nano-HE... more This article reviews the state of rapidly emerging terahertz hot-electron nanobolometers (nano-HEB), which are currently among of the most sensitive radiation power detectors at submillimeter wavelengths. With the achieved noise equivalent power close to 10^-19 W/Hz^1/2 and potentially capable of approaching NEP 10^-20 W/Hz^1/2, nano-HEBs are very important for future space astrophysics platforms with ultralow submillimeter radiation background. The ability of these sensors to detect single low-energy photons opens interesting possibilities for quantum calorimetry in the mid-infrared and even in the farinfrared parts of the electromagnetic spectrum. We discuss the competition in the field of ultrasensitive detectors, the physics and technology of nano-HEBs, recent experimental results, and perspectives for future development.
For high critical current density (J_c), a type-II superconductor must have defects or inclusions... more For high critical current density (J_c), a type-II superconductor must have defects or inclusions which pin the vortex lattice. A bundle and cold-draw process is used to produce superconducting wire with micron-sized NbTi filaments which have a nanometer-sized array of ferromagnetic pins. The wire with the highest Jc has a pin diameter of 4 nm and a pin spacing of
We investigate the single photon detection and reset mechanisms in superconducting nanowires, whi... more We investigate the single photon detection and reset mechanisms in superconducting nanowires, which have received recent, widespread attention for use in applications requiring fast optical and near infrared photon counting. These devices are fabricated from ...
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