Abstract: The invention is directed to a swipe with at least one ionization reagent associated with the swipe for detecting target analytes and methods of detecting the target analyte molecules that can indicate the presence of, for example, explosives, narcotics, chemical warfare agents, biological warfare agents, or toxins. The swipe can be used to transfer molecules from a surface to the swipe for further analysis. In particular, the swipes can include an ionization reagent that is preferably a low volatility compound and capable of forming ionization reagent-analyte complexes with target analytes. The swipe can also include multiple ionization reagents with different volatilities such that they are released sequentially during a thermal ramp-up. Alternatively, the swipe can have multiple ionization reagents associated with spatially separated portions of the swipe such that they can be releasable sequentially to detect multiple target analytes.

Abstract: A superconducting nanowire avalanche photodetector (SNAP) with improved high-speed performance. An inductive element may be coupled in series with at least two parallel-coupled nanowires. The nanowires may number 5 or fewer, and may be superconducting and responsive to even a single photon. The series inductor may ensure current diverted from a photon-absorbing nanowire propagates to other nanowires and become amplified. The series inductance may be less than 10 times the nominal inductance per nanowire, and may also be larger than a minimum inductance to avoid spurious outputs in response to a photon absorption. The series inductance may be configured to achieve a desired tradeoff between SNAP reset time and spurious outputs. For example, the series inductance may be configured achieve minimum reset time or maximum bias margin, subject to user-defined constraints. By appropriately configuring the series inductance, a systematic method of designing improved SNAPs may be provided.