Additive manufacturing (AM) of passive microwave components is of high interest for the cost-effective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE011-like resonant mode at the Rb clock frequency of ≈6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavities and indicate a good uniformity of the field amplitude across the vapor cell. Employing a time-domain Ramsey scheme on one of the SLA cavities, high-contrast (34%) Ramsey fringes are observed for the Rb clock transition, along with a narrow (166 Hz linewidth) central fringe. The measured clock stability of 2.2 × 10−13 τ−1/2 up to the integration time of 30 s is comparable to the current state-of-the-art stabilities of compact vapor-cell clocks based on conventional microwave cavities and thus demonstrates the feasibility of the approach….
The Neuchâtel Time Frequency Laboratory: at the heart of innovative precision
The Time Frequency Laboratory at Neuchâtel University recently announced the validation of a prototype for a microwave cavity, a crucial component in atomic clocks. The innovation is in the production of these components using 3D printers, a first in the field. But are you familiar with how atomic clocks operate and their applications ? (Article)
Interview of Gaetano Mileti, Deputy director of the Time and Frequency Laboratory of Neuchatel (RTS, CQFD, 23.02.2018)(French)
Design and Power | 07.03–09.03.2019
Teacher: Theresia Leuenberger
The workshop deals with the questions of power in relation to design processes (collaboration with multiple actors) and the working of design (perception, use).
We worked in groups to talk about some of our projects and try to understand these design issues.
John Harrison. The invention of longitude
John Harrison (1693–1776) was a self-educated English carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the problem of calculating longitude while at sea.
Harrison’s solution revolutionized navigation and greatly increased the safety of long-distance sea travel. The problem he solved was considered so important following the Scilly naval disaster of 1707 that the British Parliament offered financial rewards of up to £20,000 (equivalent to £3.09 million in 2019) under the 1714 Longitude Act.
In 1730, Harrison presented his first design, and worked over many years on improved designs, making several advances in time-keeping technology, finally turning to what were called sea watches. Harrison gained support from the Longitude Board in building and testing his designs. Toward the end of his life, he received recognition and a reward from Parliament.
Marine chronometer
History of longitude
Carl Sagan, Cosmos
Carl Sagan (1934-1996) was an American astronomer, cosmologist, astrophysicist, astrobiologist, author, science popularizer, and science communicator in astronomy and other natural sciences. He is best known for his work as a science popularizer and communicator (Cosmos: A Personal Voyage (Television series)). His best known scientific contribution is research on extraterrestrial life (SETI Program), including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them.
The Time Machine, H.G. Wells
The Time Machine is a science fiction novella by H. G. Wells, published in 1895 and written as a frame narrative. The work is generally credited with the popularization of the concept of time travel by using a vehicle that allows an operator to travel purposely and selectively forwards or backwards in time. The term “time machine”, coined by Wells, is now almost universally used to refer to such a vehicle.
The Time Machine has been adapted into three feature films of the same name, as well as two television versions, and a large number of comic book adaptations. It has also indirectly inspired many more works of fiction in many media productions.
La Jetée, Chris Marker
A man is a prisoner in the aftermath of World War III in post-apocalyptic Paris, where survivors live underground in the Palais de Chaillot galleries. Scientists research time travel, hoping to send test subjects to different time periods “to call past and future to the rescue of the present”. They have difficulty finding subjects who can mentally withstand the shock of time travel. The scientists eventually settle upon the prisoner; his key to the past is a vague but obsessive memory from his pre-war childhood of a woman he had seen on the observation platform (“the jetty”) at Orly Airport shortly before witnessing a startling incident there. He did not understand exactly what happened, but knew he had seen a man die.
After several attempts, he reaches the pre-war period. He meets the woman from his memory, and they develop a romantic relationship. After his successful passages to the past, the experimenters attempt to send him into the far future. In a brief meeting with the technologically advanced people of the future, he is given a power unit sufficient to regenerate his own destroyed society.
Upon his return, with his mission accomplished, he discerns that he is to be executed by his jailers. He is contacted by the people of the future, who offer to help him escape to their time permanently; but he asks instead to be returned to the pre-war time of his childhood, hoping to find the woman again. He is returned to the past, placed on the jetty at the airport, and it occurs to him that the child version of himself is probably also there at the same time. He is more concerned with locating the woman, and quickly spots her. However, as he rushes to her, he notices an agent of his jailers who has followed him and realizes the agent is about to kill him. In his final moments, he comes to understand that the incident he witnessed as a child, which has haunted him ever since, was his own death.
Mapping time, the space of a moment
How to represent time without using animation? The figuration of time has been present in various forms in cartography since time immemorial and all over the world. If today time is mainly represented by animated maps – which corresponds to the possibilities offered by computer techniques -, other modes of representation have existed. In this article, we wish to revive the possibility of representing time through a succession of still images.
French article
Why to measure the time?
RTS Archive (French)
Why to measure the time?
What is an atomic clock?
What are atomic clocks used for?
What accuracy for atomic clocks?
Zeitmessung: Atomuhren der Weltklasse
Bern-Wabern, 21. März 2006, 21.03.2006 – Die Schweiz ist wieder Weltspitze in der Zeitmessung: Einem Forscherteam des Observatoriums Neuenburg gelang es, die modernste Cäsium-Atomuhr der Welt weiter zu stabilisieren. Das ist ein entscheidender Durchbruch auf dem Weg zu einer noch genaueren Zeitmessung.
Mesure du temps : Horloges atomiques à la pointe mondiale
Berne-Wabern, 21 mars 2006, 21.03.2006 – La Suisse maintient sa place de pointe dans la mesure du temps : une équipe de chercheurs de l’Observatoire de Neuchâtel a franchi un pas décisif dans l’amélioration de la stabilité de son horloge, qui est déjà l’une des plus performantes au monde. Il s’agit d’un progrès significatif dans la mesure du temps.