News › Fraun­ho­fer IOF • »Applied Pho­to­nics Award 2021« – Award cerem­ony with Nobel Prize Win­ner Rein­hard Genzel

Best Bache­lor The­sis (1,000 €)

Kat­rin Bihr (Furt­wan­gen Uni­ver­sity): “Depth mea­su­re­ment in endo­sco­pic 3D systems”

Endo­scopy is the exami­na­tion and illu­mi­na­tion of hol­low organs or the inside of the body with the aid of a medi­cal instru­ment known as an »endo­scope«. Ste­reo endo­sco­pes con­sist of two came­ras and allow a three-dimen­sio­nal view. Howe­ver, when using 3D endo­sco­pes, distances and sizes can curr­ently only be roughly esti­ma­ted by the sur­geon via the depth per­cep­tion of the instru­ment. This impairs the objec­tive docu­men­ta­tion of a finding.

As part of her bachelor’s the­sis, Kat­rin Bihr deve­lo­ped a method for deter­mi­ning the depth of an object point in front of the endo­scope. The ability to mea­sure tis­sue and tumors inside the body can repre­sent a major advance for dia­gno­stics and tre­at­ment in medi­cine. This can, for exam­ple, enable pro­ce­du­res in can­cer the­rapy to be car­ried out more gently or in a more tar­ge­ted man­ner. But the approach to depth mea­su­re­ment is also appli­ca­ble bey­ond the field of endo­scopy: ste­reo camera sys­tems can poten­ti­ally be used whe­re­ver the camera posi­tion is fixed rela­tive to the object sur­face and only a small space is available.

Best Mas­ter The­sis (2,000 €)

Luise Hoff­mann (Claus­thal Uni­ver­sity of Tech­no­logy): »Manu­fac­tu­ring and cha­rac­te­riza­tion of fem­to­se­cond laser-alloyed nickel mesh elec­tro­des for the alka­line water electrolysis«

Fem­to­se­cond lasers offer a wide range of appli­ca­ti­ons in medi­cine and metro­logy. Howe­ver, they are also coming into focus in the field of mate­ri­als pro­ces­sing. Espe­ci­ally in sur­face pro­ces­sing, the modi­fi­ca­tion of their phy­si­cal pro­per­ties enables new fields of appli­ca­tion for a wide variety of mate­ri­als such as semi­con­duc­tors, glas­ses, and metals.

In her master’s the­sis, Luise Hoff­mann pres­ents a newly deve­lo­ped three-stage fem­to­se­cond laser alloy­ing pro­cess. Here, the cata­lyst mate­rial is incor­po­ra­ted into the sur­face from thin films. The method pre­sen­ted by Hoff­mann is applied to pro­duce sta­ble metal alloys of molyb­denum as cata­lyst on nickel net elec­tro­des for the hydro­gen evo­lu­tion side (HER) in alka­line elec­tro­ly­sis of water (AEL), in addi­tion to crea­ting a struc­tu­red surface.

The pro­cess deve­lo­ped by Hoff­mann gives rise to a large num­ber of fur­ther areas of appli­ca­tion, which are also of inte­rest to the indus­trial sec­tor. Due to cur­rent cli­mate policy goals, one of the main focu­ses of cur­rent rese­arch is on the gene­ra­tion and sto­rage of hydro­gen in order to mini­mize elec­tro­che­mi­cal loss phenomena.

Best Dis­ser­ta­tion (3,000 €)

Dr. Tobias Schna­bel (Bau­haus Uni­ver­si­tät Wei­mar): “Pho­to­ca­ta­ly­tic degra­da­tion of phar­maceu­ti­cal micro­pol­lut­ants on sup­ported catalysts“

Pol­lut­ants in our water that can be remo­ved only slightly or not at all by muni­ci­pal was­te­wa­ter tre­at­ment plants are refer­red to as »anthro­po­ge­nic micro­pol­lut­ants«. In his dis­ser­ta­tion, Dr. Tobias Schna­bel descri­bes how water can be puri­fied with the help of a pho­to­nic sys­tem. Schnabel’s work deals with the use of UV‑A LEDs as an exci­ta­tion source for car­rier-bound photocatalysts.

For this pur­pose, new reac­tion con­cepts and cata­lysts for the oxi­da­tion of phar­maceu­ti­cal micro­pol­lut­ants in the matrix of muni­ci­pal was­te­wa­ter were deve­lo­ped and inves­ti­ga­ted. As part of his work, a pho­to­nic sys­tem for the cold com­bus­tion (»pho­to­ca­ta­ly­tic oxi­da­tion«) of phar­maceu­ti­cals in the efflu­ent of muni­ci­pal was­te­wa­ter tre­at­ment plants was deve­lo­ped, set up and tes­ted under real con­di­ti­ons. The results have shown that it is pos­si­ble to treat muni­ci­pal was­te­wa­ter with a pho­to­ca­ta­ly­tic sys­tem with rela­tively low energy requirements.

Jury award for high poten­tial for uti­liza­tion and appli­ca­tion (1,500 €)

Dr. Chris­toph Stih­ler (Fried­rich Schil­ler Uni­ver­sity Jena): “Trans­verse mode insta­bi­lity – Insights into modal energy trans­fer in high-power fiber lasers”

Due to their uni­que pro­per­ties, fiber lasers enable a wide range of appli­ca­ti­ons alre­ady today. High-energy laser radia­tion is gene­ra­ted by means of a spe­cial thin glass fiber and the prin­ci­ple of light con­duc­tion. This radia­tion has an extre­mely high beam qua­lity com­pared to that of other laser tech­no­lo­gies and can thus be focu­sed on an extre­mely small area. As a result, appli­ca­ti­ons can be car­ried out with the hig­hest pre­cis­ion. In addi­tion, the large sur­face area of the fiber enables effi­ci­ent coo­ling. In the past, the average power of fiber lasers could thus be increased almost expo­nen­ti­ally wit­hout having to sacri­fice the excel­lent beam qua­lity. In 2010, howe­ver, this deve­lo­p­ment came to an abrupt halt. Fiber lasers had advan­ced into a power range in which a new type of ther­mal effect could be obser­ved. This cau­sed tem­po­ral and spa­tial fluc­tua­tions to des­troy the other­wise sta­ble and ideal beam pro­file of the fiber laser. Since then, the phe­no­me­non of so-cal­led »trans­verse mode insta­bi­lity« (TMI) has hin­de­red fur­ther increa­ses in the power of fiber lasers with ideal beam quality.

With his PhD the­sis, Dr. Chris­toph Stih­ler aims to con­tri­bute to a fun­da­men­tal under­stan­ding of mode insta­bi­lity and thus to over­co­ming the limi­ta­ti­ons resul­ting from it. With his fin­dings, he has deve­lo­ped new stra­te­gies for sup­pres­sing TMI, paving the way for fur­ther power sca­ling of fiber lasers. The hig­her average power with ideal beam qua­lity has mul­ti­ple poten­tial appli­ca­ti­ons, inclu­ding the rem­oval of cor­ru­ga­ted space debris by bom­bar­ding debris with powerful ground- or satel­lite-based lasers.