Real-time ultrasound sensing with a mode-optimized photonic crystal slab
Bibliographic record
Abstract
Integrated photonic sensors can provide large scale, flexible detection schemes. Photonic crystal slabs (PCSs) offer a miniaturized platform for wideband, sensitive ultrasound detection by exploiting the photoelastic effect in water. However, poor modal overlap with the sensing medium and non-negligible absorption loss of the aqueous medium have previously limited PCS sensor performance. In this study, we detail the development and optimization of a PCS-based acoustic sensor by adding to it a low-loss high-index polymer cladding layer. Exploiting a mode-optimized TM-like optical resonance present in a PCS, with high bulk index sensitivity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow class="MJX-TeXAtom-ORD"><mml:mo>></mml:mo></mml:mrow><mml:mrow class="MJX-TeXAtom-ORD"><mml:mn>600</mml:mn></mml:mrow><mml:mspace width="thickmathspace"/><mml:mrow class="MJX-TeXAtom-ORD"><mml:mi mathvariant="normal">n</mml:mi><mml:mi mathvariant="normal">m</mml:mi><mml:mrow class="MJX-TeXAtom-ORD"><mml:mo>/</mml:mo></mml:mrow><mml:mi mathvariant="normal">R</mml:mi><mml:mi mathvariant="normal">I</mml:mi><mml:mi mathvariant="normal">U</mml:mi></mml:mrow></mml:math> ) and quality factor Q ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow class="MJX-TeXAtom-ORD"><mml:mo>></mml:mo></mml:mrow><mml:mrow class="MJX-TeXAtom-ORD"><mml:mn>8000</mml:mn></mml:mrow></mml:math> ), we demonstrate real-time ultrasound sensing at a noise equivalent pressure of 170 Pa ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>1.9</mml:mn><mml:mspace width="thickmathspace"/><mml:mrow class="MJX-TeXAtom-ORD"><mml:mi mathvariant="normal">P</mml:mi><mml:mi mathvariant="normal">a</mml:mi></mml:mrow><mml:mrow class="MJX-TeXAtom-ORD"><mml:mo>/</mml:mo></mml:mrow><mml:msqrt><mml:mrow class="MJX-TeXAtom-ORD"><mml:mi mathvariant="normal">H</mml:mi><mml:mi mathvariant="normal">z</mml:mi></mml:mrow></mml:msqrt></mml:math> ). The PCS sensor is backside-coupled to an optical fiber, which, along with its intensity-based ultrasound-sensing architecture, will allow us to scale up easily to a 2D array. This work paves the way to a sensitive compact ultrasound detector for photoacoustic-based diagnostics and monitoring of tissue.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".