Rese­arch

Ato­mic Vapor-Cell based Opti­cal Fre­quen­cy Refe­ren­ces

Time­kee­ping for next genera­ti­on glo­bal navi­ga­ti­on satel­li­te sys­tems

Opti­cal fre­quen­cy refe­ren­ces have long sur­pas­sed the sta­bi­li­ty of their micro­wa­ve coun­ter­parts in lab envi­ron­ments. Remai­ning chal­len­ge to make use of the­se devices in field expe­ri­ments is a more com­pact and robust design at the same per­for­mance level. Our aim is to deve­lop micro­in­te­gra­ted opti­cal refe­ren­ces com­pri­sing ato­mic vapor cells towards low size, weight and power (SWaP) ato­mic clocks. We focus on sys­tems uti­li­zing tran­si­ti­ons bey­ond the D2 line in rubi­di­um, such as two-pho­ton 5S → 5D, to reach sta­bi­li­ties regimes rele­vant for glo­bal navi­ga­ti­on satel­li­te sys­tems (GNSS).

Team: J. Klu­ge, D. Kohl, M. Eisebitt, Dr. K. Dörings­hoff

Stron­ti­um Opti­cal Clocks

Clock tech­no­lo­gies based on ther­mal and ultra­cold stron­ti­um for space and indus­try

One natu­ral ato­mic can­di­da­te for pre­cisi­on clock app­li­ca­ti­ons is stron­ti­um employ­ing a rich elec­tro­nic term struc­tu­re fea­turing broad, nar­row and ultra-nar­row tran­si­ti­ons. In one type of clocks cur­r­ent­ly deve­lo­ped in our group, we uti­li­ze Ram­sey-Bor­dé Inter­fe­ro­me­try on a ther­mal stron­ti­um beam. By deve­lo­ping com­pact phy­sics packa­ges inclu­ding, e.g., low SWaP ovens, the­se acti­vi­ties aim for an ato­mic beam clock fit­ting insi­de a 19“ rack, sui­ta­ble for ope­ra­ti­on in space with frac­tio­n­al fre­quen­cy sta­bi­li­ties of below 10-15. Other acti­vi­ties use stron­ti­um 88 atoms, which will be laser-coo­led, trap­ped and inter­ro­ga­ted in a 1D opti­cal lat­ti­ce. Matu­ring the­se tech­no­lo­gies for space app­li­ca­ti­ons opens up new pos­si­bi­li­ties for fun­da­men­tal sci­ence like clock based gra­vi­ta­tio­nal wave detec­tion, sear­ches for dark mat­ter and tests of local posi­ti­on inva­ri­an­ce.

Team: M. Schlö­sin­ger, O. Fart­mann, C. Pyr­lik, Dr. H. Zim­mer­mann, Dr. Ing­ma­ri Tiet­je, Dr. V. Schkol­nik

Minia­tu­riz­a­ti­on of Ato­mic Phy­sics Packa­ges

Enab­ling tech­no­lo­gies for UHV com­pa­ti­ble inte­gra­ti­on and addi­ti­ve manu­fac­tu­ring

Minia­tu­riz­a­ti­on of expe­ri­men­tal set­ups and opti­cal sys­tems is the key towards the next genera­ti­on of com­pact quan­tum sen­sor tech­no­lo­gy and is ope­ning up new pro­spects in nume­rous fiel­ds of app­li­ca­ti­on. Our acti­vi­ties inclu­de mode­ling of opti­cal com­pon­ents, hybrid micro-inte­gra­ti­on of elec­tro-opto-mecha­ni­cal devices, sys­tem design and veri­fi­ca­ti­on. In par­ti­cu­lar we inves­ti­ga­te the use of addi­ti­ve manu­fac­tu­ring of cer­a­mics and ther­mo­plastics for com­pact and scala­b­le assem­blies, the deve­lo­p­ment of minia­tu­ri­zed free-space opti­cal sys­tems for ato­mic mani­pu­la­ti­on in UHV envi­ron­ments and the qua­li­fi­ca­ti­on of joi­ning tech­ni­ques for use in UHV sys­tems and space app­li­ca­ti­ons.

Team: A. Stie­kel, C. Zim­mer­mann, B. Der­meik, Dr. S. Schwert­fe­ger, M. Christ

Atom Optics and Inter­fe­ro­me­try with Bose-Ein­stein Con­den­sa­tes

Engi­nee­ring of cohe­rent mat­ter wave packets in free fall

Quan­tum sen­sors based on ultra­cold atoms are pro­mi­sing can­di­da­tes to impact our future dai­ly lives with app­li­ca­ti­ons in navi­ga­ti­on sys­tems and geo­de­sy, but are also pro­po­sed for tests of fun­da­men­tal phy­sics with unri­va­led sen­si­ti­vi­ties. Due to the point source-like cha­rac­te­ris­tics and low expan­si­on velo­ci­ties, BECs con­sti­tu­te ide­al quan­tum pro­bes for mat­ter-wave inter­fe­ro­me­try. In absence of gra­vi­ty, the free and unper­tur­bed evo­lu­ti­on of a BEC can be exten­ded signi­fi­cant­ly, which is cru­cial for ent­e­ring new regimes in high-pre­cisi­on mea­su­re­ments. Our part in the QUAN­TUS col­la­bo­ra­ti­on com­pri­ses ground work with con­cep­tu­al stu­dies inclu­ding the pre­pa­ra­ti­on of mat­ter-wave packets as source for novel inter­fe­ro­metric sche­mes and BEC inter­fe­ro­me­try in micro­gra­vi­ty towards tes­ting the uni­ver­sa­li­ty of free fall with quan­tum mat­ter.

Team:J. Pahl, S. Kant­hak, M. Humai­ra, S. Ven­gala­das, Dr. D. Rei­che

Laser Sys­tem Deve­lo­p­ment for Har­sh Envi­ron­ments

Diode laser sys­tems for cold ato­mic devices on mobi­le plat­forms

We focus on deve­lo­p­ment of com­pact and robust high power laser sys­tems, which are key tech­no­lo­gy for the genera­ti­on and cohe­rent mani­pu­la­ti­on of cold ato­mic gases. Each mobi­le plat­form fea­tures its own chal­len­ging envi­ron­ment. We work on ground-based micro­gra­vi­ty plat­forms, such as the ZARM drop tower in Bre­men, and in future also on the Ein­stein Ele­va­tor in Han­no­ver. Each plat­form sets high demand on the size, weight and power con­sump­ti­on of the expe­ri­ment, and espe­cial­ly the laser sys­tems must with­stand high acce­le­ra­ti­ons during ope­ra­ti­on and main­tain fre­quen­cy and inten­si­ty locks. Even hig­her deman­ds are impo­sed for laser sys­tems on space-bor­ne micro­gra­vi­ty plat­forms, like sound­ing rockets or small satel­li­tes. Here, we are inte­res­ted in hard- and soft­ware tools for stand-alo­ne sys­tems with reli­able auto­no­mous ope­ra­ti­on.

Team: O. Anton, J. Pahl, S. Kant­hak, G. Kaplan, I. Papa­da­kis, Dr. V. Schkol­nik

Ato­mic Quan­tum Memo­ries in Space

Towards phy­si­cal­ly secu­re, long-distance com­mu­ni­ca­ti­ons

Quan­tum com­mu­ni­ca­ti­on is usual­ly limi­ted to around a few hund­red kilo­me­ters due to the expo­nen­ti­al los­ses in opti­cal fibers. Quan­tum repeaters (QR) based on heral­ded sto­rage of ent­an­gled sta­tes have been pro­po­sed to over­co­me this direct trans­mis­si­on limit. Howe­ver, they are still limi­ted to around a few thousand kms. On the other hand, space-based quan­tum links whe­re chan­nel loss sca­les main­ly poly­no­mi­al­ly offer ano­t­her solu­ti­on to this pro­blem. In this case, howe­ver, the com­mu­ni­ca­ti­on distance is limi­ted to the line-of-sight distance of the satel­li­te which is around 2000 km for low earth orbit. Wit­hin this con­text, in order to reach tru­ly glo­bal distan­ces, we are working on QR archi­tec­tures ope­ra­ting in space, inclu­ding expe­ri­men­tal work towards buil­ding space-com­pa­ti­ble quan­tum memo­ries with warm and cold ato­mic gases.

Team: M. Jutisz, Dr. E. Da Ros, Dr. M. Gün­doğan

Ato­mic ensem­ble based sen­sors

Inte­gra­ted devices for magne­to­myo­gra­phy and velo­ci­me­try
Enhan­ced light-mat­ter inter­ac­tion due to non­line­ar opti­cal effects in reso­nant ato­mic media would help deve­lop dif­fe­rent types of sen­sors for dif­fe­rent app­li­ca­ti­ons. In this con­text our group uti­li­zes warm alka­li vapors towards crea­ting por­ta­ble, rug­ged magne­tic field and velo­ci­ty sen­sors. We deve­lop a minia­tu­ri­sed sin­gle-beam ato­mic magne­to­me­ter device with sub-pico-Tes­la sen­si­ti­vi­ty with small SWaP bud­get for bio­lo­gi­cal and medi­cal app­li­ca­ti­ons. On the other hand, we aim to deve­lop a por­ta­ble, mul­tia­xis velo­ci­ty sen­sor enab­led by slowing down light pul­ses in a reso­nant ato­mic medi­um.

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