The researchers transmitted light pulses of 13 fs duration (1 fs = 1 millionth billionth of a second) over one meter distance, with the pulses only stretching to about double of the initial duration. “Currently, no other fiber-based technique is capable of such little distortion”, says Dr. Günter Steinmeyer.
In comparison, using similar fibers of a more conventional make, pulse stretching to more than 50 times the original duration was observed. The novel fibers may be useful in medical applications, e.g., for guiding femtosecond pulses to the patient in a flexible manner. In their advance online section, Nature Photonics reports about this novel type of fiber.
The MBI fiber consists of many glass capillaries and guides the light on a diameter equal to about half the diameter of a human hair. In contrast to conventional hollow fibers, which consist of capillaries of equal diameter, the diameter changes in MBI’s novel fiber (see figure). This can be understood as gluing straws side by side, yielding a tube of straws when the first and the final straw are also glued together. Repeating this procedure with straws of different diameter and fitting the resulting tubes into one another ultimately yields a structure similar to MBI’s fiber. For manufacturing the fiber, the researchers have used 5 such tubes of straws. Referring to the systematic change in capillary diameter, the researchers call such a structure chirped.
Launching ultrashort laser pulses into such a fiber, the chirped structure acts to distribute detrimental resonances over a wide wavelength range, which would otherwise add up at one wavelength if the capillaries had all the same diameter. The fiber was manufactured at Saratov State University in Russia.
The researchers see one particularly interesting medical application of their fiber in photodynamic therapy. For this method, a photosensitizer is accumulated in cancerous cells. Exposing the photosensitizer to light, a substance is formed which causes fatal damage of the tumor cells. Using ultrashort laser pulses rather than continuous light, the selectivity of this therapeutic method could be significantly improved as the photoexcitation could be limited to the immediate vicinity of the focal area, whereas tissue layers immediately above or below the interaction zone would stay unharmed.
So far, however, no fiber was available to guide the required short light pulses to the patient in a flexible way without severe distortions through an endoscope. The chirped fiber structure could also be beneficial for diagnostic applications in biology and medicine, such as in two-photon microscopy, a method that allows for three-dimensional resolution of smallest biological structures at effective suppress.
First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester
Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy