Exceptional points and the ring laser gyroscope

Horstman, Luke; Hsu, Nan‐Jung; Hendrie, James; Smith, David D.; Diels, Jean‐Claude

doi:10.1364/prj.369521

Cited by 27 publications

(20 citation statements)

References 22 publications

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“…Further improvements of the setup can be stabilization of the utilized lasers, increase of the OPO power, working at a shorter OPO wavelength, and squeezing of the phase. In addition, introduction of large resonant dispersion (such as a Gires–Tournois interferometer) into the OPO cavity can significantly amplify the frequency difference between the two circulating pulses [ 16 ].…”

Section: Discussionmentioning

confidence: 99%

Phase Nanoscopy with Correlated Frequency Combs

Zhu

Lenzner

Diels

2022

Sensors

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This study addresses any sensor based on measuring a physical quantity through the phase of a probing beam. This includes sensing of rotation, acceleration, index change, displacement, fields… While most phase measurements are made by detecting an amplitude change in interfering beams, we detect instead a phase change through a relative frequency shift of two correlated frequency combs. This paper explores the limit sensitivity that this method can achieve, when the combs are generated in an Optical Parametric Oscillator (OPO), pumped synchronously by a train of femtosecond pulses separated by half the OPO cavity round-trip time. It is shown that a phase difference as small as 0.4 nanoradians can be resolved between the two pulses circulating in the cavity. This phase difference is one order of magnitude better than the previous record. The root-mean-square deviation of the measured phase over measuring time is close to the standard quantum limit (phase-photon number uncertainty product of 0.66). Innovations that made such improved performances possible include a more stable OPO cavity design; a stabilization system with a novel purely electronic locking of the OPO cavity length relative to that of the pump laser; a shorter pump laser cavity; and a square pulse generator for driving a 0.5 mm pathlength lithium niobate phase modulator. Future data acquisition improvements are suggested that will bring the phase sensitivity exactly to the standard quantum limit, and beyond the quantum limit by squeezing.

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Section: Discussionmentioning

confidence: 99%

Phase Nanoscopy with Correlated Frequency Combs

Zhu

Lenzner

Diels

2022

Sensors

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“…These findings demonstrate that EPs should generally be avoided for sensors that utilize laser cavities. It should be emphasized that the scale factor diverges more rapidly for higher-order EPs [34], and we have ignored the effects of saturation and nonlinearity, which can also modify the divergence rate [37,46,65]. It's clear that these effects will also modify eigenmode skew and the divergence of K, but our analysis does not explicitly treat these cases.…”

Section: | Sk mentioning

confidence: 99%

“…One reason EPs have been of recent interest is because the sensitivity of the frequency difference between the eigenstates to an external perturbation, i.e., the scale factor, has been shown to diverge at an EP [16][17][18][19][20][21][22]. The boost in scale-factor sensitivity has now been demonstrated experimentally in passive and active fast-light cavities [21][22][23][24][25][26][27], optomechanical and nanoparticle detection schemes [30,31], and CRs including RLGs [32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Non-Hermitian gyroscopes: Can exceptional points increase sensor precision?

Smith

Chang

Shahriar³

2022

Optical and Quantum Sensing and Precision Metrology II

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We show that exceptional-point (EP) sensors are fundamentally limited by excess noise owing to eigenmode nonorthogonality, to the extent that the enhancement in precision (the magnitude of the scale-factor enhancement divided by the square-root of the linewidth-enhancement factor 1/2 | | / SK ) is never greater than unity. Indeed, in the vicinity of an EP a hole of reduced precision opens up in parameter space, where the precision drops rapidly to zero within regions of deadband or unbroken PT-symmetry. Outside of these zero-sensitivity regions the precision is nonzero, approaching its maximum value of1 SK  at the EP. EPs, therefore, represent discontinuous transitions between these two regimes. We find that this behavior is universal, with the hole appearing regardless of the type of EP. Therefore, EPs should generally be avoided for sensors that utilize laser cavities. Moreover, we illustrate that a laser containing a medium at the critical anomalous dispersion is simply operating at an EP. Therefore, this limitation also applies to laser sensors based on fast light.

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“…For APT gyroscope, the frequencies are locked in APT S regime before EP, creating a measuring dead band for rotations [78,79]. While in the APT B regime (shaded regimes in Fig.…”

Section: B Linear Apt Gyroscopementioning

confidence: 99%

“…After that, several EP-based gyroscopes have been proposed using PT or APT symmetry [45,[71][72][73], loss regulation [74,75], and dissipative coupling [76][77][78]. Compared with PT gyroscope, APT gyroscope does not need gain, thus can be kept at EP more accurately.…”

Section: Introductionmentioning

confidence: 99%

Anti-$\mathcal{PT}$-symmetric Kerr gyroscope

Zhang,

Peng,

et al. 2021

Preprint

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Non-Hermitian systems can exhibit unconventional spectral singularities called exceptional points (EPs). Various EP sensors have been fabricated in recent years, showing strong spectral responses to external signals. Here we propose how to achieve a nonlinear anti-parity-time (APT ) gyroscope by spinning an optical resonator. We show that, in the absence of any nonlinearity, the sensitivity or optical mode splitting of the linear device can be magnified up to 3 orders than that of the conventional device without EPs. Remarkably, the APT symmetry can be broken when including the Kerr nonlinearity of the materials and, as the result, the detection threshold can be significantly lowered, i.e., much weaker rotations which are well beyond the ability of a linear gyroscope can now be detected with the nonlinear device. Our work shows the powerful ability of APT gyroscopes in practice to achieve ultrasensitive rotation measurement.

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Exceptional points and the ring laser gyroscope

Cited by 27 publications

References 22 publications

Phase Nanoscopy with Correlated Frequency Combs

Phase Nanoscopy with Correlated Frequency Combs

Non-Hermitian gyroscopes: Can exceptional points increase sensor precision?

Anti-$\mathcal{PT}$-symmetric Kerr gyroscope

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