@article{63732,
  abstract     = {{Time lenses have been recognized as crucial components for manipulating ultrafast optical pulses in various applications, from ultrafast spectroscopy to the interfacing of optical quantum systems. A time lens is characterized by its chirp rate, which determines the focusing strength of the time lens, and accurate knowledge of this chirp is critical for precise dispersion compensation and minimizing aberrations. Here, we introduce a tunable time aperture model for sinusoidal time lenses that provides a more accurate estimate of the effective chirp rate without modifying the device. We derive a closed-form expression for the maximum phase error and show how it depends on the time aperture. We experimentally demonstrate a 1.6-fold improvement in spectral bandwidth compression of Gaussian pulses compared to the conventional approach. Our framework offers a practical tool for designing efficient temporal optical systems, benefiting applications in both classical and quantum optics where accurate spectro-temporal shaping is essential.}},
  author       = {{Kapoor, Sanjay and Sośnicki, Filip Maksymilian and Karpiński, Michał}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  number       = {{9}},
  publisher    = {{AIP Publishing}},
  title        = {{{Aberration-optimized electro-optic time lens model using a tunable aperture}}},
  doi          = {{10.1063/5.0270904}},
  volume       = {{10}},
  year         = {{2025}},
}

@article{63744,
  abstract     = {{Orbital angular momentum (OAM) modes are an important resource used in various branches of quantum science and technology due to their unique helical structure and countably infinite basis. Generating light that simultaneously carries high-order orbital angular momenta and exhibits quantum correlations is a challenging task. In this work, we present a theoretical approach to the generation of correlated Schmidt modes carrying OAM via parametric down-conversion (PDC) in cascaded nonlinear systems (nonlinear interferometers) pumped by Laguerre–Gaussian beams. We demonstrate how the number of generated modes and their population can be controlled by varying the pump parameters, the gain of the PDC process, and the distance between the crystals. We investigate the angular displacement measurement uncertainty of these interferometers and demonstrate that it can overcome the classical shot noise limit.}},
  author       = {{Scharwald, Dennis and Gehse, Lucas and Sharapova, Polina}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  number       = {{1}},
  publisher    = {{AIP Publishing}},
  title        = {{{Schmidt modes carrying orbital angular momentum generated by cascaded systems pumped with Laguerre–Gaussian beams}}},
  doi          = {{10.1063/5.0229802}},
  volume       = {{10}},
  year         = {{2025}},
}

@article{61931,
  abstract     = {{<jats:p>Recent research revealed that single-mode vertical-cavity surface-emitting lasers under spin injection (spin-VCSELs) have the potential to revolutionize laser technology for short-haul optical communications. While previous studies have focused solely on single-mode operation, this study introduces multimode spin-VCSELs. We experimentally demonstrate the existence of multi-resonant polarization dynamics when spin is injected, a phenomenon previously unobserved. The development opens the door to significantly faster and more efficient optical communication systems by harnessing the collective behavior of multiple laser modes. Furthermore, we lay the groundwork for understanding multimode operation through the extension of the single-mode spin–flip model, which forms the basis for present and future analyses of multimode spin-laser operation. This work is an important step toward realizing the full potential of spin-VCSELs and, thus, enables significantly improved performance of spin-VCSEL-based optical networks in the future.</jats:p>}},
  author       = {{Diiankova, Uliana and Drong, Mariusz and Pusch, Tobias and Michalzik, Rainer and Lindemann, Markus and Gerhardt, Nils Christopher and Hofmann, Martin R.}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  number       = {{10}},
  publisher    = {{AIP Publishing}},
  title        = {{{Multimode vertical-cavity surface-emitting lasers under spin injection}}},
  doi          = {{10.1063/5.0286998}},
  volume       = {{10}},
  year         = {{2025}},
}

@article{61110,
  abstract     = {{<jats:p>By analyzing the physics of multi-photon absorption in superconducting nanowire single-photon detectors (SNSPDs), we identify physical components of jitter. From this, we formulate a quantitative physical model of the multi-photon detector response that combines the local detection mechanism and local fluctuations (hotspot formation and intrinsic jitter) with the thermoelectric dynamics of resistive domains. Our model provides an excellent description of the arrival-time histogram of a commercial SNSPD across several orders of magnitude, both in arrival-time probability and across mean photon number. This is achieved with just three fitting parameters: the scaling of the mean arrival time of voltage response pulses, as well as the Gaussian and exponential jitter components. Our findings have important implications for photon-number-resolving detector design, as well as applications requiring low jitter, such as light detection and ranging (LIDAR).</jats:p>}},
  author       = {{Sidorova, Mariia and Schapeler, Timon and Semenov, Alexej D. and Schlue, Fabian and Stefszky, Michael and Brecht, Benjamin and Silberhorn, Christine and Bartley, Tim}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  keywords     = {{Jitter, PNR, SNSPD}},
  number       = {{8}},
  publisher    = {{AIP Publishing}},
  title        = {{{Jitter in photon-number-resolved detection by superconducting nanowires}}},
  doi          = {{10.1063/5.0273752}},
  volume       = {{10}},
  year         = {{2025}},
}

@article{55553,
  abstract     = {{<jats:p>Cryogenic opto-electronic interconnects are gaining increasing interest as a means to control and readout cryogenic electronic components. The challenge is to achieve sufficient signal integrity with low heat load processing. In this context, we demonstrate the opto-electronic bias and readout of a commercial four-pixel superconducting nanowire single-photon detector array using a cryogenic photodiode and laser. We show that this approach has a similar system detection efficiency to a conventional bias. Furthermore, multi-pixel detection events are faithfully converted between the optical and electrical domains, which allows reliable extraction of amplitude multiplexed photon statistics. Our device has a latent heat load of 2.6 mW, maintains a signal rise time of 3 ns, and operates in free-running (self-resetting) mode at a repetition rate of 600 kHz. This demonstrates the potential of high-bandwidth, low noise, and low heat load opto-electronic interconnects for scalable cryogenic signal processing and transmission.</jats:p>}},
  author       = {{Thiele, Frederik and Lamberty, Niklas and Hummel, Thomas and Bartley, Tim}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  number       = {{7}},
  publisher    = {{AIP Publishing}},
  title        = {{{Optical bias and cryogenic laser readout of a multipixel superconducting nanowire single photon detector}}},
  doi          = {{10.1063/5.0209458}},
  volume       = {{9}},
  year         = {{2024}},
}

@article{33673,
  abstract     = {{<jats:p> Superconducting Nanowire Single Photon Detectors (SNSPDs) have become an integral part of quantum optics in recent years because of their high performance in single photon detection. We present a method to replace the electrical input by supplying the required bias current via the photocurrent of a photodiode situated on the cold stage of the cryostat. Light is guided to the bias photodiode through an optical fiber, which enables a lower thermal conduction and galvanic isolation between room temperature and the cold stage. We show that an off-the-shelf InGaAs–InP photodiode exhibits a responsivity of at least 0.55 A/W at 0.8 K. Using this device to bias an SNSPD, we characterize the count rate dependent on the optical power incident on the photodiode. This configuration of the SNSPD and photodiode shows an expected plateau in the single photon count rate with an optical bias power on the photodiode above 6.8 µW. Furthermore, we compare the same detector under both optical and electrical bias, and show there is no significant changes in performance. This has the advantage of avoiding an electrical input cable, which reduces the latent heat load by a factor of 100 and, in principle, allows for low loss RF current supply at the cold stage. </jats:p>}},
  author       = {{Thiele, Frederik and Hummel, Thomas and Protte, Maximilian and Bartley, Tim}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  keywords     = {{Computer Networks and Communications, Atomic and Molecular Physics, and Optics}},
  number       = {{8}},
  publisher    = {{AIP Publishing}},
  title        = {{{Opto-electronic bias of a superconducting nanowire single photon detector using a cryogenic photodiode}}},
  doi          = {{10.1063/5.0097506}},
  volume       = {{7}},
  year         = {{2022}},
}

@article{16112,
  author       = {{Höpker, Jan Philipp and Gerrits, Thomas and Lita, Adriana and Krapick, Stephan and Herrmann, Harald and Ricken, Raimund and Quiring, Viktor and Mirin, Richard and Nam, Sae Woo and Silberhorn, Christine and Bartley, Tim}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  title        = {{{Integrated transition edge sensors on titanium in-diffused lithium niobate waveguides}}},
  doi          = {{10.1063/1.5086276}},
  year         = {{2019}},
}

@article{47948,
  abstract     = {{Mach-Zehnder electro-optic modulators (EOM) based on thin-film lithium niobate bonded to a silicon photonic waveguide circuit have been shown to achieve very high modulation bandwidths. Open eye-diagram measurements made in the time domain of beyond-small-signal modulation are used to support the modulation-sideband measurements in showing that such EOM’s can support high-frequency modulations well beyond 100 GHz.}},
  author       = {{Wang, Xiaoxi and Weigel, Peter O. and Zhao, Jie and Rüsing, Michael and Mookherjea, Shayan}},
  issn         = {{2378-0967}},
  journal      = {{APL Photonics}},
  keywords     = {{Computer Networks and Communications, Atomic and Molecular Physics, and Optics}},
  number       = {{9}},
  publisher    = {{AIP Publishing}},
  title        = {{{Achieving beyond-100-GHz large-signal modulation bandwidth in hybrid silicon photonics Mach Zehnder modulators using thin film lithium niobate}}},
  doi          = {{10.1063/1.5115243}},
  volume       = {{4}},
  year         = {{2019}},
}