effective x
(2) Creation through SHG
To urge effective x(2) At the same time, what looks like the phase in the lower conversion process matches, a space shipping exchange was created using the experimental setting shown in the extensive data 1A. Micureoresonator is carefully controlled for visual mode and infrared. These frequencies were monitored using an infrared -adjusted laser (1560 nm). It was transferred by frequency using the polyetium polyetium crystal crystal. Once this is completed, the frequency of the laser near infrared was set on the echo of the cavity. After that, a spacecraft field was built and a second twins, as shown elsewhere16. A stable condition was achieved within a few seconds, and the network lasted for a long time without external excitement. The efficiency of the second energy conversion and x(2) Then the force was characterized by the use of a low -energy infrared pump, as shown in the expanded data 1B. We have noticed a 780 -megawatled two -megawatts compatibility signal when 41 megawatts of Laser Energy 1560 nm were launched in the wave guide. This corresponds to the efficiency of the second consensus (or) From 651 % per watt. We believe that this value is limited to the saturation of the second consensual process and the presence of generating frequencies to 520 nm (reference. 42).
For comparison, the second reconciliation efficiency can also be estimated from the rate of the size of the size of the size of the photon size P And the visual pump energy (780 nm) PFacebook In the SPDC process10:
Ster
(1)
where yourGo, to ((yourGo, andIt is the rate of losing the (outer) cavity loaded in the near infrared mode. At 1.5 megawatts pump on the chip, the rate of the generation of the photon pair was measured as 800 kHz. Using the above expression rates and the visual loss of the main text, the calculated SHG efficiency or = 624 % per watt, in a close agreement with the above -measured value. As part, we expect this account to reduce the efficiency of Shg, because, as mentioned in the main text, the distribution of shipping fades in the presence of a 780 nm pump (see methods for more details). In particular, an average of 800 kHz was recorded a few minutes after the 780 nm pump in the tooth, so the charging distribution will not be as strong as the initial state. In general, the agreement of these two conclusive values may be lucky in light of experimental uncertainty.
Spec
We used the AA AA, the nitrogenic liquid cooled with spectral measurements (Pylon IR 1024-1.7). She had an amount of more than 75 %. The spectrum scale contains 300 lines per millimeter (1.2 micron fire) and efficiently more than 50 % for wavelengths less than 1600 nm.
Dependence on temperature from the lengths of the photon waves pair
The wavelengths of the photon pairs that were created are determined by the frequency match between the visual pump position and the family of the band near the infrared. To determine this matching status, the distant infrared family was measured first using the Mach-Zehnder Calibour43. Resonance frequency OhM the situation MIt can be approximated as the Taylor series in relation to the situation in Oh0 It is defined to have a relative position number M= 0:
$ hanging
(2)
where DJ he J First degree dispersion factor. especially, D1/2π equals FSR, and D2 It is the second -class dispersion factor in the situation M= 0, as shown in the expanded data 2A M = 0. It gives the equivalent installation D2/2π = −863.7 KHz.
Resonant frequency transactions DOh / /DR. It was measured directly by changing the temperature of the micerorersonator chip using a curator. The results appear in the extended data 2B. Using these measurements, the rate of relative frequency dislocation (DOhFacebook/ /DR.– 2DOhand/ /DR.It was identified to be 8814.8 MHz−1where OhFacebook and Ohand The resonance frequency of the semi -visible conditions close to IR respectively. Along with negativity D2 It is measured above, other than the dismantling of the SPDC process from slope to warm when changing the temperature of the resonance. Accordingly, suppose the deteriorating SPDC process is identical with a frequency to the nearby infrared number M = 0 at temperature R.0 ((OhFacebook((R.0) = 2Oh0((R.0)). After that, using the expansion of dispersion (equation (2)), the state of irregular frequency in the temperature R. It can be written in the name,
Step} _ {0}
(3)
Step} _ {{\ rm {Vis}}}/\ Delta T-2 \ Delta {\ OMEGA} _ {{\ rm {IR}}}/\ Delta T) (t- {t} _ {0}). $$.
(4)
Where the status numbers +M And –M They are the relative status numbers of the conditions close to infrared radiation participating in the SPDC process. From the equation (4) and the use of the measured value of DOhFacebook/ /DR. – 2DOhand/ /DR. The Spring Laboratory for the Raqir Class was calculated as a function of the length of the photon wave with a visit to 0.0131 kg–2And that was used to draw the spring function in the 2D Figure.
Display the frequency range for the transformed photon pairs
In the automatic automatic transformation process, couples of proximity to infrared can hesitate with the visual pump mode because the slight frequency mismache caused by dispersion can be smaller than the dispute width. The frequency matching status can be written as follows:
$$ {d} _ {2} {m} _ {\ max}^{2}-{d} _ {2} {m _ _ {\ min}^{2} = 2 \ delta \ OMEGA, $$, $$
(5)
Where ±MUpper (±MminuteIt is the largest (smaller) relative situation number from the identical pairs of the frequency, and δOh=Oh / / S.It is a full width in the maximum echo near infrared. In the deteriorating case, Mminute = 0. MUpper Then it is given before,
$ hanging
(6)
Using current resonance values, MdegreeUpperIt is calculated to be 5.7, which is consistent with the dark blue tracking in Figure 2C.
Case MdegreeUpper = 1 given byD2 > 2δOh= 2Oh0 / / S.where S.It is a loaded cavity S.Near -red infrared factor. By rewritingD2 In terms of fsr δ NFSR (Hirtz) and a scattering teacher, the speed of the wave guide for2 (Reference. 43The following design status of SPDC appears:
$$ Q \ Delta {\ nu} _ {\ text {fsr}}^{2}> \ frac {n} {{\ rm {\ pi}} {\ lambda}} _ {0} | {\ beeta} _ {2} | }, $$
(7)
where to0and NIt is a wavelength and an effective index for the situation M= 0, respectively. for2 Associated with D2like \ ({\ beeta} _ {2} = –n {d} _ {2}/c {d} _ {1}^{2} \)And it was calculated to be 540 ps2how much−1Using parameters from the previous section. CIt symbolizes the speed of light in a vacuum. For other model values for Si Lold Si3N4The system, and this givesS.D NFSR2 > 5.49 x 1011Ghz2. AssumingS.= 100 million, which can be easily achieved through this system, δNFSR> 74 GHz is sufficient to ensure a monitoring SPDC.
In the case of irregular, the equation can be adjusted as follows:
$ Hanging
(8)
where \ (\ Overline {m} = ({m} _ {\ text {max}}+{m} _ {\ min})/2 \) and \ (\ Delta M = ({m} _ {\ text {max}}-{m} _ {\ min})/2 \). At 23.7 ° C, \ (\ Overline {m} = 16 \) And δ MIt is calculated to be 1. This is consistent with the notes, as for long and short wavelengths of the spectrum, photon flows are observed in only one adjacent position on each side of the strongest position. At higher temperatures, no side tops were observed in the spectrum.
Z
(2) Measurement
theZ(2)(( R.The husband’s generation rates were measured by a pair of SNSPDS 1.55 microns with 85 % efficiency provided by Quantique. SNSPDS signals were recorded by an ID900 transformer with a time accuracy of 2 NS.
Acting time deterioration x
(2)
As mentioned in the main text, the SPDC rate in timely decomposition is observed. We believe this results from multiple electrons in the delivery range by 780 nm pump. These electrons will gradually neutralize the shipment of space, which reduces effectiveness x(2). This section is looking at the speed of this effect. It is experimentally difficult to rebuild the dissolution directly from the SPDC rate, because the SPDC rate is sensitive to the temperature and fragmentation of the laser. Instead, we have chosen charging monitoring with the SHG signal when wiping the 1560 nm lasers across the ring. We recorded the peak value for the second consensual signal, as shown in the expanded data Figure 1B. This measurement is appointed by a group of different separation processes and must be less affected by the temperature change.
The experimental preparation is the same as in the expanded data. Figure 1 a. The satellite charging was introduced for the first time through SHG as shown in the section “Effectivex(2)Creation through Shg. Next, the 1560 nm laser was stopped and a laser laser is 780 nm for its nomination to simulate the SPDC condition. After each 15 -second period, the 780 nm signal was turned off and the laser of 1560 nm was checked across the ringing to collect the value of the second compatibility. Two pump forces are used 780 nm (0.5 and 1.5 megawatts). The result appears in the extended data. As expected, the decomposition was faster with high pump strength. Also note that with the increase in time, the data deviated significantly from the inception and the decrease in the decadence. Possible mechanisms that can affect SHG efficiency include changes in the pump laser or polarization. Since the SPDC measurement in the main text requires a few minutes to wait for a slide temperature to achieve a stable condition, noticeable decay times correspond to our observation that the SPDC rate can be observed for several minutes.