Active optical gyroscope with controllable...

Active optical gyroscope with controllabledispersion.

Eugeniy E. Mikhailov, Owen Wolfe, Irina Novikova1,Simon Rochester, Dmitry Budker2,

1

2

LPHYS, 14 July 2016

Eugeniy E. Mikhailov (W&M) Towards fast gyroscope LPHYS, 2016 1 / 17

Sagnac effect and cavity response

Ω

beamsplitter

input

detector

output

E cw

E ccw

∆p = ±ΩRt = ±2AΩc

∆f = f0∆pp

1ng

= ∆fempty1ng

Group index

ng(f ) = n + f0∂n∂f

vg = c/ng

Cavity response enhanced if ng < 1 i.e. under the fast light conditionShahriar et al., PRA 75, 053807 (2007)


EIT - slow light

| 2 〉

| 1 〉

| 3 〉

δ

∆ HFS

| 4 〉

Ω 1Ω 2

∆ 1


N-bar with four-wave mixing - fast and with gain

| 2 〉

| 1 〉

| 3 〉

δ

∆ HFS

| 4 〉

Ω 1Ω 2

∆ 1Ω 3

∆ 3

γ 42

γ 41


N-bar with Doppler averaging

Refractive index Absorption

Stationary atoms

Room temperatureDoppler averaged


N-bar levels and fields diagram

Artificial atom 87Rb atom

F=2

F=1

F’=2

F’=1

m=1m=0m=-1m=-2 m=2

F’=2

F’=1

F’=3

F’=0

5P

5P

5S

3/2

1/2

1/2


The first gyro setup and its performance

Finesse = 20

→ Pulling 1/200

D1 tuned around Fg = 1→ Fe = 1,2

E. Mikhailov, et al. Optical Engineering, Issue 10, 53, 102709, (2014)


The first gyro setup and its performance

P.F . =∆fdispersive

∆fempty=

1ng

∆fempty = f0∆pp

Finesse = 20 → Pulling 1/200

E. Mikhailov, et al. Optical Engineering, Issue 10, 53, 102709, (2014)Eugeniy E. Mikhailov (W&M) Towards fast gyroscope LPHYS, 2016 8 / 17

Gyro lasing: theory vs. experiment

|2〉

|1〉

|3〉

δ

∆HFS

|4〉

Ω 1Ω 2

δ1Ω 3

δ 3Ω 4

δ 2 P

δ 4


Gyro pulling and amplitude vs. gyro cavity detuning

Cavity detuning span 150 MHz. Pulling ×100


Pulling factor with increased cavity finesse (20→ 70)

|2〉

|1〉

|3〉

δ

∆HFS

|4〉

Ω 1Ω 2

δ1Ω 3

δ 3Ω 4

δ 2 P

δ 4

λ/2

FIBER

LENS

PBSLENS

D1 LASER

Rb Cell

MAGNETIC

SHIELDING

Rb87

PBS

D2 LASER

CAMERA

FIBERBEAMSPLITTER

SCOPE

PD

SpectrumAnalyzer

FASTPD

P.F . =∆fdispersive

∆fempty

=1ng

∆fempty = f0∆pp

−600 −400 −200 0 200−0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

20150803: Pulling factor vs. D2 laser detuning

D2 laser detuning from F

g=2 −> F

e=3, MHz

Pu

llin

g f

acto

r

−600 −400 −200 0 2000

0.05

0.1

0.15

0.2

20150803: Pulling factor averaged vs. D2 laser detuning


g=2 −> F

e=3, MHz

Pu

llin

g f

acto

r

−600 −400 −200 0 200−100

−90

−80

−70

−60

−50

20150803: Beat−note span vs. D2 laser detuning


g=2 −> F

e=3, MHz

Fre

qu

en

cy ,

MH

z

−600 −400 −200 0 200−90

−85

−80

−75

−70

20150803: Beat−note amplitude vs. D2 laser detuning


g=2 −> F

e=3, MHz

Be

at−

no

te a

mp

litu

de

, d

Bm

0 1 2 3 4−0.1

0

0.1

0.2

0.3

0.4

20150804: Pulling factor vs. D2 power

D2 power, mW

Pu

llin

g f

acto

r

0 1 2 3 4−0.1

0

0.1

0.2

0.3

0.4

20150804: Pulling factor averaged vs. D2 power

D2 power, mW

Pu

llin

g f

acto

r

0 1 2 3 4−86

−84

−82

−80

−78

−76

−74

20150804: Beat−note span vs. D2 power

D2 power, mW

Fre

qu

en

cy ,

MH

z

0 1 2 3 4−90

−85

−80

−75

−70

20150804: Beat−note amplitude vs. D2 power

D2 power, mW

Be

at−

no

te a

mp

litu

de

, d

Bm


Dependence on total pumps power


Dependence on 87Rb vapor density

Low pumps power

1.5 2 2.5 3 3.5

x 1012

0.06

0.08

0.1

0.12

0.14

0.16

Vapor Density, (Nparticles

cm−3

)

Pu

llin

g f

acto

r

20151002: Pulling factor vs. Vapor Density

1.5 2 2.5 3 3.5

x 1012

0.06

0.08

0.1

0.12

0.14

0.16

Density, 1/cm3

Pu

llin

g f

acto

r

20151002: Pulling factor averaged vs. Vapor Density

1.5 2 2.5 3 3.5

x 1012

−440

−420

−400

−380

−360

−340


cm−3

)

Fre

qu

en

cy ,

MH

z

20151002: Beat−note span vs. Vapor Density

1.5 2 2.5 3 3.5

x 1012

−86

−84

−82

−80

−78

−76


cm−3

)B

ea

t−n

ote

am

plit

ud

e,

dB

m

20151002: Beat−note amplitude vs. Vapor DensityHigh pumps power

2 4 6 8 10 120.2

0.4

0.6

0.8

1

1.220160708: Pulling factor vs. Density

Density, 1012

/cm3

Pu

llin

g f

acto

r

2 4 6 8 10 12

0.7

0.8

0.9

1

1.120160708: Pulling factor averaged vs. Density

Density, 1012

/cm3

Pu

llin

g f

acto

r

2 4 6 8 10 12660

680

700

720

740

760

78020160708: Beat−note span vs. Density

Density, 1012

/cm3

Fre

qu

en

cy ,

MH

z

2 4 6 8 10 12−68

−66

−64

−62

−6020160708: Beat−note amplitude vs. Density

Density, 1012

/cm3

Be

at−

no

te a

mp

litu

de

, d

Bm


Gyroscope laser multi-mode structure

Gyro beatnote spectrum vs. empty cavity offset

Empty cavity detuning, MHz

Beatn

ote

fre

quency, M

Hz

0 20 40 60 80 100 120 140 160

−400

−300

−200

−100

0

−100 −80 −60

−400

−350

−300

−250

−200

−150

−100

−50

0

50

dBm

Fre

quency, M

Hz

Cell temperature 110◦C, total power 350 mW.Modes pulling factors are 0.54, 0.45, 0.04.


High power regime: dependence on D2 detuning

Pumps power ≈ 6 mW Pumps power ≈ 180 mW


People

Irina Novikova, ShuangLi Du, Owen Wolfe, Demetrious Kutzke (WM),Dmitry Budker, Simon Rochester (Rochester Scientific).


Summary

0 20 40 600

10

20

30

40

50

60

Empty cavity shift, MHz

Dis

pe

rsiv

e c

avity s

hift,

MH

z

−600 −400 −200 0 200−0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

20150803: Pulling factor vs. D2 laser detuning


g=2 −> F

e=3, MHz

Pulli

ng facto

r

−600 −400 −200 0 2000

0.05

0.1

0.15

0.2

20150803: Pulling factor averaged vs. D2 laser detuning


g=2 −> F

e=3, MHz

Pulli

ng facto

r

−600 −400 −200 0 200−100

−90

−80

−70

−60

−50

20150803: Beat−note span vs. D2 laser detuning


g=2 −> F

e=3, MHz

Fre

quency , M

Hz

−600 −400 −200 0 200−90

−85

−80

−75

−70

20150803: Beat−note amplitude vs. D2 laser detuning


g=2 −> F

e=3, MHz

Beat−

note

am

plit

ude, dB

m

Improved puling factor: 0.005→ 0.3 withincreased finesse (20→ 70)Increased pump lasers power (6 mW→200 mW) pushed the pulling factor to 1Setup has widely tunable responseinfluenced by

pump lasers power and detuningdensity of 87Rb atomscavity finesse

This allows us to tune the response of thesystem on demand

We are grateful for financial support to


Sagnac effectCavity responseModification of dispersionExperimental realizationGyro lasing simulationsGyro lasingPulling dependence on detunings, power, Rb densityPulling sensitivity at high power

People

Active optical gyroscope with controllable...

Documents

Transcript of Active optical gyroscope with controllable...