Invited Speakers - Special Sessions

Microfabricated alkali vapor cells are an asset for compact atomic devices but are limited by traditional sealing methods and single-axis optical designs. This work introduces two scalable solutions. First, we present an approach for collectively filling and sealing cesium cells, potentially supporting higher purity and compatibility with anti-relaxation coatings. Then, we report a wafer-level method that creates three orthogonal optical paths using laser-assisted etched glass and thermal reflow. 

We present a fully-integrated, scalable platform for the integration of photonic integrated circuits (PICs) and microfabricated atomic vapor cells. We demonstrate the device performance by interrogation of the rubidium D2 lines via free-space, grating-coupled, and evanescent spectroscopy. 

 We present a simple framework for the ensemble option (Option 2) in the redefinition of the SI second, showing that it corresponds to fixing the barycenter of a constellation of residuals associated with the contributing transitions when expressed in fractional frequency deviations. This linear formulation clarifies the definition, enables straightforward uncertainty propagation using the CCTF recommended frequencies, and naturally supports a full ensemble-based realization of the SI second. 

 This presentation on behalf of the CCTF Task Force on the Roadmap to the Redefinition of the Second will give an update on the work of the task force. The mission is to provide an analysis of the different types of options for the redefinition and of the specific atomic transitions and species that might be used to implement these options. 

 Integrated high power (Watt-level) sources are desired for frequency and time metrology and various other applications such as telecom, medical devices, and remote sensing. We use large-mode-area (LMA) gain waveguides in rare-earth doped gain media to achieve Watt-level output power devices on a SiN on insulator (SiNOI) fabrication platform. We demonstrate a DBR laser with more than 1 Watt output power and various other devices ranging from Q-switched lasers to on-chip mode-locked lasers. 

 The paper reviews the development of photonic integrated circuits integrated with MEMS vapor cells for atomic systems with examples of saturated absorption spectroscopy and cold-atoms in a MEMS cells as demonstrators. 

We showcase the potential for ultralow-noise integrated photonic lasers based on seed laser stabilization to an on-chip spiral interferometer. We achieve a record low Allan deviation for an integrated-chip laser of 5.6×10^-14 corresponding to a linewidth of 12 Hz centered at 1348 nm. 

Photonic integrated circuits based on silicon nitride have been developed that attain losses below 3dB/meter, unlocking applications from microcombs, frequency agile low noise lasers, to parametric amplfiers and femtosecond laser frequency combs on chip based on Erbium. 

 The paper reviews the development of photonic integrated circuits integrated with MEMS vapor cells for atomic systems with examples of saturated absorption spectroscopy and cold-atoms in a MEMS cells as demonstrators. 

 Compact ultrastable lasers have a variety of out-of-the-lab applications in low noise signal synthesis and sensing. We review our work in sub-1 mL vacuum-gap cavities that achieve 4x10-14 fractional frequency stability and on robust laser locking methods for chip-scale lasers. 

Laser cavity-solitons (LCS) arise in nested laser–microresonator systems as self-localized pulsed states sustained by the interplay of Kerr nonlinearity, gain dynamics, and slow nonlocal effects. Here we review their properties, including robust and long-term operation and present our recent results on their metrological features

High-Q microresonators enable access to nonlinear optical phenomena at milliwatt power levels. This capability, now available on CMOS foundry lines, is enabling a new generation of remarkable chip-integrated devices and systems. Following a brief overview of their history and early nonlinear demonstrations, this presentation will highlight recent advances in devices and systems driven by high-Q microresonator technology. Particular emphasis will be placed on the discovery of the photogalvanic effect in silicon nitride, which has unlocked access to second-order nonlinearities in this workhorse photonic integration platform. This capability, previously restricted to non-centrosymmetric dielectrics, is combined with self-injection locking of near-IR telecom lasers to generate high-coherence visible light on chip. The recent demonstration of ultra-high-Q Ge–silica resonators in the visible and violet bands will also be discussed, enabling direct generation of high-coherence visible light.