26 December 2010

Fir and fairy lights

Here milder than recent days; the wind has changed; a new energy is in the air.

Something of a hiatus since last posting. In part being away from here; in part technological disagreement with this device; in part Christmas and preparations for it at home and in the other job; but largely due to a mute lack of inspiration as to what to say. Some thoughts and reading and explorations into the world of electronic engineering and its affiliates have been happening during this time, but nothing has formed that is nugget sized and deemed worthy of presentation here. And to that end I am going to embed in Silicon Photonics, an introduction (Reed and Knights), and Mathematical Techniques (Jordan and Smith) for some time, amidst the fir and fairy lights with a cup of coffee, and see what comes. Happy Christmas.

5 December 2010

Intermittent scrubber

Sunny and chilly Sunday. Stove lit, cats dozing.

Today’s is a tale of time spent in a clean room. I am a part time cleaner (although the house that I inhabit isn’t famously reflective of my skills in this field). It is a job that I find rewarding – the work, which is gratifyingly physical, has the satisfaction of being a defined occupation, completed (and well done, I hope), at the end of the day. Both science and art seem, to me, to be rather open-ended. The word ‘rather’ in this comment is a gross understatement; actually both art and science are infinite. On occasion it can be helpful to imagine them as finite (comprehensible, controllable, constrainable), since thinking of infinite things can be mentally wearing, but nonetheless their enormity is somehow ever evident. In both fields each accomplishment is merely another small step along an eternal path that leads nowhere (and everywhere?). These days, being an intermittent scrubber somehow grounds me in an otherwise limitless world.

But the cleanliness of the clean room that I encounter on this occasion is not my responsibility, thank goodness, for here they try to keep out any particles bigger than 10 micrometers; that is, any speck or fleck bigger than a hundredth of a millimetre in its longest dimension is banished. This room is kept clean in order for work on wafers to be undertaken, among other things; here the wafers are cleaned and coated, acid and acetone baths remove residues, photoresist is applied, lithographic images transferred and patterns etched; the carving of waveguides.

In order to enter the space we must suit up, in a little room between the outside world and the spotless sanctum; I, being a visitor, am given a white papery boiler suit to wear (with matching shoe covers and bathing cap). I am relieved of my sketchbook and pencil, for shards of paper and graphite fragments circulating in the air are vetoed; inside I will be given special sky-blue, shed-free pieces of paper, and allowed use of a biro. Walking across a sticky floor mat (to retain any last minute hitchhikers from the soles of our feet) we enter through the inner door.

My first impression on walking into the room is of several machines with outstretched arms – mutely crying out for interaction. These are sealed boxes, clean within, with arm-length rubber gloves attached in order for manipulations inside them to be possible. But the air pressure in the boxes is such that the arms are inflated outwards, at their ends squishy sausagey fingers, air-filled and bloated. One machine that we repeatedly brush past has a pair of arms at hip height, hip width apart; a static dance partner awaiting animation. It is strangely intimate to stand between the outstretched hands, their airy touch on my boiler-suited hips.

I shadow Renzo, from the bright white light of the main room into the subdued red and yellow lights of small, light-sensitive, filtered rooms off to the side. He has recently completed his PhD, riding high in the light of his recent viva, and is continuing in the group as a post-doc. Today he is experimenting with transferring a pattern of waveguides onto a new wafer that he has been sent from a collaborator. A silicon germanium wafer. The wafer is mirror shiny on one side and matt grey on the other, one edge of its circular circumference cut off, indicating the plane of the integral crystal structure. He carefully breaks it into smaller pieces, and then these are rather laboriously processed via a number of machines and procedures to clean and dry them, prior to being coated with a UV-sensitive resist. Finally the wafer is exposed to UV light, and the image transferred (the next stage will be the etching, but there is no time for that today). Through the course of these repetitions I have been wandering in and out, and exploring the main room, intermittently returning to the ‘yellow room’ to touch base. I meet a woman who is keeping digital readouts under control on one of the armed boxes; she is working on photovoltaics, one of the other big and groundbreaking research areas going on in this building. I see a sputter machine, whose name conjures images of custard pies, or similar, being discharged at unexpected moments. And I stumble upon an aspect of the cleaning capability of this room, a rather fetching turquoise and violet Dyson; a moment of the mundane amidst the state of the art.

1 December 2010

Vehicular uncertainty

If I drive from home to the University of Surrey and you want to know where I am at a given time on my journey then if you know my speed and what time I left home you should be able to calculate roughly where I have got to. (Bear in mind that the queue at the Costa coffee at Exeter Services can be desperately slow, so perhaps factor in a random variable for that). However, if you want to know where I am exactly at any given time, you will not be able to know how fast I am going at that point because in effect you have to stop time at the moment you want to know where I am, in order to accurately calculate my position. And similarly if you want to know how fast I am travelling (relative to the road, I believe) you will have to accept that my position at that time will remain approximate, since calculation of my speed requires that I am moving past any given point as you catch me on your speed camera.

If you want to subvert these complications of quantic information gathering, you could just call me on my mobile, and I can let you know both my position and speed at any time. Maybe understanding the subtleties of quantum theory is merely about being correctly selective about who, or what, you ask the questions of.

Yesterday and today

Yesterday.

Man, it’s quiet here this morning. A hard frost has made the surface of the world white, and even the birds are audibly subdued because of the cold. The sky is that very pale mauvey grey type of luminous white that looks as if it is heavy with snow, but may just pass by without releasing its load. There is something about the colour that seems as if all the light is trapped up there in the cloud and is bouncing around in dancing forms, prismatic separations meeting to reform in new shades. Multiplexing and demultiplexing. Almost imperceptible hues of pink, yellow and green shimmer and retreat, embedded amongst the more obvious greys and blues. All that mobility and energy silently rolling around in the heavens.

My friend Sara will testify to my inability to accept the world in terms of polarities (I take great pleasure in regularly exuberantly discussing it with her!); to me everything could never be so flat. Black and white; hot and cold; male and female; wave and particle; how restrictive. So it is with that view that I am trying to make sense of the nature of light. I imagine that since many greater intellects than mine have long pondered the understanding of this intrangible character, with meticulous and rigorous scientific analysis as well as deep thought, that I am not going to find an easy answer any time soon. However, a little undaunted, I again set out on the voyage (which was what formerly led me to try to make head or tail of Feynman) – explorations into light.

And today.

December. A beautiful still and clear morning here, blue sky and sun. Much of the rest of the country white today, but here the edges of the world just shimmer with the pale grey of a hard frost. Quiet.

I spent a frustrating day yesterday trying to learn about quantum physics, trying to understand the models of waves, rays and photons, but found that each piece of writing that I read was built on foundations of words and concepts that I did not fully understand. Each book or article requiring study of another, more fundamental, one in order for it to be fully illuminating. I begin to wonder if there is actually a bottom to this search, or whether I shall find myself back at the most recent of papers on silicon photonics at the end of a circuit of attempted learning. A ring of resonating words and ideas that starts and ends within itself.

I think that for the moment I shall raise my head from the words and go to let my mind wander out in the world, go to look at some watery waves, and feel sunny photons on my face.

29 November 2010

The domain of textbooks

(Day Three) Lab meeting at 10 am in what feels like a subterranean room, despite the fact it is on the ground floor. The lighting in here is flat and artificial – the kind that sucks all the life out of you. I am the first to arrive, and so sit for a few minutes in the quiet (being gradually devitalised?) awaiting the arrival of who knows who. I am not sure where to sit at the table – is there a hierarchy of places? Does the boss always have the same position / chair? I chose what I hope will be an involved but inconspicuous seat and wait. The members of the group arrive in briefly interspersed dribs and drabs. I introduce myself and the names I am presented with in return stay with me for variable amounts of time. The boss breezes in, friendly and with an upbeat energy to him; it feels like he is often on the edge of laughter. After a few general words he introduces me and asks the members of the group to tell me who they are and what they are doing in the group, as they report on the status of their efforts. We work our way round the table and I make some (variously comprehensible) notes in my book (Fred: postdoc, optical modulators, encodes electrical signal to optics, integrating electronics and photonics. Rob: new PhD student, work following on from Renzo’s stuff, erascible gratings (runcible spoons?). Fuller’s is Graham’s favourite beer, etc.). When I am introduced to Ufang (postdoc, passive silicon photonic devices, multiplexing and demultiplexing, etc.), Graham mentions how excited they were when they found out that Dr Hu was coming to work in the group. I am again cheered by the humour. (I am also intrigued by Ufang’s lab book, open on the desk next to me, as it seems to be comprised almost exclusively of images and diagrams, with no visible text). The introductions continue; I know there are a Milosh and a Milan amongst the small throng, but am later confused as to which way round the names apply.

At one point a conversation evolves around the table concerned with the objectivity of experimentation, after one of the students has referred to following a certain course of testing as it looked like it was producing “better” results than others. Graham, who is evidently sharply aware of everything going on in this room, instantly picks up on and questions the comment. The profundity of the implications of this conversation do not appear to be lost on anyone, despite the relative subtlety with which it is approached. Education and learning are manifest.

I again meet Goran, who is a Royal Society Fellow, and senior member of the group. He had previously shown me around the department when I visited. He and I will, later today, speak at some length about the process of teaching, which he is evidently deeply interested in and concerned by, and learning, which I am also fascinated by. I am looking forward to attending some of his lectures in the coming weeks. After a little more general discussion of upcoming conferences, equipment failures, and with the date of the next meeting fixed, the meeting ends and we disperse. Back out of the manufactured lighting of the (apparent) ion beam underworld into the daylight; vitalities re-inflating; I blinking in response to another dose of intense exposure to unfamiliar words and names.

As I write I am conscious that I am intentionally trying to make myself unaccountable, unreliable - the chronology and order in which my missives are presented is nonlinear. Introducing deliberate paradox into my writings. Some words are presented as they were recorded at the time, from notes made in situ, while some are embellished with the flights of fancy that time and distance can convey. This is not a scientific document. I am not illustrating the world as the scientists are describing it – that is the domain of the textbooks. I am not working here as scientist, even thought that mind set is deeply embedded within me. I am here to explore and to understand, to misinterpret, to stimulate, to imagine. I wish to manipulate words to convey feelings, ideas, thoughts; to translate the science into another form; to embrace the freedom that my role as artist lends me.
  
Back home, Rosie is in the airing cupboard. We are all retreating to the proximity of sources of heat. Waking up this morning was, as the last few days, to feel the chill of exposed areas, and the knowledge that warmth will be regained (after the comfort of the bed had been left) only when the stove has been lit and got hot. Complaining would be churlish (I love this place, this beautiful place) and make me sound like a little old lady, ever obsessed by the weather and distracted by chilly bones. But it is cold here at the moment. (The toothpaste is extremely reluctant to come out of the tube when squeezed these last days, as it has gone solid - I believe it is a state referred to as being frozen. M + T expressed concern about the temperature of my bathroom while visiting last week – I fear these words will not reassure them). Maybe the intermittent bursts of central heating that the residence side of the residency are conveying will yet convince me that living in my rustic rural idyll could do with something of a more comforting coating of urban embellishment. Yet there is something of a basal excitement and aliveness associated with the pleasure of lighting a fire to get heat; an appreciation of the fundamental physicality of this world. And it is weirdly good to be bundled up in three t-shirts, three jumpers, a bodywarmer and a scarf as I write; my typing is a bit hampered as my arms are sticking out sideways as a result of all the padding.

26 November 2010

The width of a colour

Today is my niece’s birthday and I have failed to get her present into the post as I was waiting in for an electrician at the necessary time yesterday. Bad aunty (but I hope she’ll like the present, so am optimistic about being forgiven). It is after eight already and the glowing yellow light of the sun, as it appears above the field to the east, is illuminating my wall and the trees in front of me; the last leaves are stunning shades of golden orange and russet, still against the pale blue sky beyond. A beautiful morning.

I have only a few minutes as I must go to do another job for the day, but wanted to write something I had been thinking about yesterday with regard to truth and subjectivity, in art and in science, in fact and in fiction. It is not a new thought, to me, and when gone into properly is quite long (especially the fully illustrated version), but there is a kernel of it that I wanted to ponder here, since it is embedded within all that I set before you; my truth that I present to you.

Bugger... I have just rewritten the next sentence several times and scrapped them all – it seems that the truth is not being readily accessible just now; toying with me as it wriggles around in my head, knowing that time is chewing at my heels. Today is not the occasion for it to be laid bare here; it will not stay still long enough for me to pin it to this page. So instead I shall offer a thought; a question, which to me looks like it may be connected, but may just as well not be (and maybe has a very simple answer – if so please do illuminate me). As I sit here at the computer I have been looking out at the trees across the way and wondering how many shades of green or brown (etc) there are? (I believe it is a question that Pantone also consider, although they are probably interested in what difference the (human) eye can discriminate, which is a different question.) What I want to know is whether there is a smallest fundamental unit of wavelength? Since I understand photons as having a finite unit size this question also translates in my head as to whether there is something akin to a photon equivalent of colour change?

On that note I’ll go and get into another world for the day. Answers on a postcard please (and I’ll tell you about my Holmes and Watson thoughts tomorrow).

25 November 2010

Here and there

Here

All is quiet here.
As quiet as a windy dusk. The trees undulate and ripple in the gusty wind. The last of the commuting seagulls head on past, northwards to the coast. The blackbirds and moorhen squawk and chatter as they settle down in the dimming. The first observed bat flits about, a pipistrelle I think, a regular dusky site this lone flier. A few big black birds, crows or rooks or similar, skirt the edges of the trees, then settle into their browning tops.

In the darkening light of dusk the gingko, quince yellow in the full light of the subdued November day, has become the tree in Egon Schiele’s drawing. Black stemmed with an understated tight violence of glowing orange leaves; embers along the charred skeletal branches. In the wind a few leaves lightly flutter, around and down. Most are, as yet, still held. Apparently they all go together; one day attached, the next the gnarly rigidity of the tree’s structure naked baring into the winter; its silhouette daily present in the months ahead.

And there

Last week I spent a day in the lab with Dave. He was preparing a sample for testing. Many minutes of fine tuning multitudinous knobs before ten-second experiments. Passing laser light along a waveguide, looking for losses. Microscale silicon and mere seconds of time to determine fundamentals of the physicality of this light passage.

The waveguide is being tested, designed, created. A scar in the surface of the disc. It is to pass light from point to point; pass electric current from point to point; to have both electrical and optical properties.

The light that is being projected along this silicon etching has a wavelength of 1550nm. It is in a single plane, having been passed through a polarisation filter and along polarisation-maintaining fibres. (The two possible planes are transverse electric (TE) and transverse magnetic (TM).) These planar wavelengths are in phase. This is called single mode, I think. Today it is the passive optical outputs of microscopic channels for these tightly constrained waves that are under scrutiny. We are looking for power loss in Maxender interferometers. No, my phonetic spelling in my notebook is wrong, I am unconsciously corrected, Mach Zehnder Interferometers, MZIs. Next to this name in my notebook I rapidly scrawl some words about the fact that the group are making phase modulations but want to make intensity modulators. Later, re-reading my notes, I do not understand what these are, or the differences between them, nor, in fact, what the MZI is for. In the last weeks I have learned a great deal but as yet it seems that the MZI remains mysterious.

Time shifts around between here and there, as does knowledge. Information initially superficially absorbed is broken down, reconsidered and regurgitated, slightly mutated by the process, partially congealed in a mire of other images and experiences. The process of gaining understanding is not a uniform one. Waves of all forms collide, disperse, intermingle. It began with a guileless and simple question about photomultipliers. The answer was given, but not comprehended. Still not comprehended; an as yet unreached destination on a voyage of discovery. This voyage looks set to travel out into the vast (limitless?) unmapped territories of human intellectual endeavour. The far reaches disappear into potential and discovery yet to be made. The unimagined and, as yet, unimaginable. We may believe that we have seen the earth – physical explorations recorded and globally shared through, for example, the electromagnetic radiation of the television – but in our minds and in our futures exist worlds of possibly infinite variety and creativity. Our needs, understanding, imaginations and capabilities will combine to create aspects of our ongoing existences in myriad forms.