Sunday, August 26, 2007

maybe I have a good laser after all...

I posted yesterday about how my new green laser might be defective. As it turned out, this may not actually be the case.

The beam was even dimmer today than it was the day before. However, that changed when I replaced the Duracell Coppertop batteries with Duracell Ultras. The laser is now able to sting my skin and light matches as expected. This was rather unexpected given that both types of cells have the same voltage.

It's still too early to tell whether the laser is bad. Just because it's performing well right now doesn't mean the power won't drop again. All I can do is wait and see what happens.

I do hope the issue was with the batteries and not the laser itself. If that's the case, then the only problem is that good batteries are expensive. Some hobbies just aren't cheap. :-(

back to Berkeley for my senior year

I just finished moving back to Berkeley with the help of my parents. Unlike our previous move-in days, this one didn't go without a hitch.

Dad was afraid there wouldn't be enough room in my dorm for my laptop and decided to bring an extra table from home. The table was too big to fit inside the car and had to be tied to the roof. Being a little worried it would become loose, my father stopped a total of five times along the way to make sure it was secure. Perhaps we were paranoid, but it never hurts to be careful.

We arrived at Unit 4 to find the main gates locked. The staff apparently weren't doing their job. Dad had a busy schedule and was understandably annoyed. Luckily for us, someone saw us a few minutes later and let us in.

It's hard to believe I'm already a senior in college. While I wish my break was just a bit longer, I'm also excited to meet new people. I look forward to all the wonderful things in store.

Currently listening to: "A Beautiful Day" (Nordic Beatz remix) by DJ Splash

Saturday, August 25, 2007

possibly some bad news about my new laser

Two days ago, I received a high-powered laser after winning it in a contest. It could pop balloons, light matches and sting my skin. This is consistent with the abilities of a 75 mW laser. Yet none of these things are happening anymore.

From what I've been told, lasers often have a high initial output that gradually stabilizes. This is known as the burn-in period. However, I have reasons to suspect the laser is actually defective.

The inverse-square law means the apparent brightness of a laser is proportional to the square root of its power. Because my laser is now only slightly brighter than my 5 mW one, the output is probably around 15 mW at most. In an ironic twist, my originally overpowered laser is now underperforming. I did some research and have an idea of what happened.

Caution: technical details ahead

Green lasers have four main components: the potentiometer, pump diode, and Nd:YVO4 and KTP crystals. The potentiometer controls the voltage of the 808 nm pump diode. The Nd:YVO4 converts the light from the pump diode into 1,064 nm light. The KTP then doubles that into the 532 nm green light we see.

The potentiometer in my unit was likely turned up to the maximum. This would account for the high initial output. However, the crystals likely overheated and quickly burned out.

In any case, I'm heading back to Berkeley tomorrow. I know there are laser labs in the physics department. Perhaps I can find someone to take a look at my laser...

Currently listening to: Country Mountain Bluegrass by Green Hill Music

Thursday, August 23, 2007

I got another free laser!

I recently mentioned that I won another laser in a contest at Spectra Forum. Well, my new toy just arrived. :-)

Wicked Lasers generously provided two lasers for the drawing. Though they were supposed to be the 15 mW model, the company gave out the 35 mW version because the former was sold out. According to the guy running the contest, mine actually has an output of around 75 mW. Sweet!

As expected, this laser is much brighter than the Core I received back in June. It can light red and black matches with a convex lens and pop balloons unassisted. Against my better judgment, I shined it on my finger and felt a sting after a few seconds. I definitely can't wait to bring it to parties. xD

Another nice thing is that the package included a pair of LaserShades. Laser safety is extremely important because any laser can easily cause eye damage. The goggles didn't come with a cleaning cloth, but that's hardly anything to complain about.

All that having been said, I'd like to thank Ben for hosting the contest and Wicked Lasers for making it possible in the first place. You can see pictures of my new laser here.

Update: I've posted reviews of the laser and goggles.

Wednesday, August 22, 2007

Colorado trip report

"If for some reason, the flight becomes a cruise..." -- United Airlines crew member, on water landings

I came back from Colorado early this morning. It has to be one of the most amazing places we've ever visited. The trip was a great way to end the summer.

Day 1

The flight to Denver was in the afternoon, leaving lots of free time. Dad took us to Stanford Shopping Center so my mother could redeem a Macy's coupon. Speaking of which, she also had a voucher for a free Chocolixir from the Godiva store. Sweet!

Upon arriving at Oakland International Airport, my family had lunch at a Mexican restaurant as it was around noon. The flight was mostly uneventful, although the flight attendant going over the emergency procedures was hilarious. Given that it was past 10 p.m. when we landed in Denver, my parents and I went to bed after arriving at the hotel.

Day 2

The day began with the Hammond's Candies factory tour. It was interesting to see how hard candies are made. That was a neat experience - aside from having to wear a silly hat. There were also free samples, but only two pieces per person. Stingy bastards.

We checked into our hotel in Estes Park before exploring the area. The town was absolutely beautiful, especially in the fog. The place reminded me of our stay in Canmore six years ago. I wish we had a few more days here.

Our stroll was cut short by a sudden thunderstorm. The weather was intense; there was thunder and lightning every minute or so. This was kind of scary but also made our stay in Estes Park much more memorable. The storm subsided almost as quickly as it had appeared, after which we went outside again to enjoy the fresh air.

Mom and I watched Mr. & Mrs. Smith on HBO later in the afternoon. It was funny and stupid at the same time. I also saw Solar Attack and The Volcano Disaster on the Sci-Fi Channel after dinner. They were pretty much on par with other made-for-TV disaster movies. I liked Solar Attack better but missed the ending because Dad insisted on going to the spa before it closed. Oh well.

Day 3

Rocky Mountain National Park awaited us in the morning. Though I had often seen pictures, this was our first time here in person. The scenery was better than anything in the Bay Area. I could spend the whole day here.

Before leaving, my parents and I stopped at a gift shop and bought two CDs: Country Mountain Bluegrass by Green Hill Music and The Sounds of the Rocky Mountains by Orange Tree Productions. I loved both albums and would have bought more if they weren't so expensive. Perhaps I should start checking eBay or something.

Our final destination of the day was Frisco. Great views aside, there was nothing special about this town. On the other hand, I spent the afternoon watching MythBusters on the Discovery Channel. MythBusters is easily one of my favorite TV shows.

Day 4

The highlight of the day was the Royal Gorge Bridge. At 1,053 feet above the Arkansas River, the bridge is the highest in the United States. The gorge was an incredible sight, although not for the faint of heart!

We browsed the stores and had lunch at one of the restaurants. The weather was fairly warm but not unbearably hot. On the whole, the Royal Gorge Bridge was my favorite stop. The funny thing is that we almost turned back at the entrance because it looked unassuming from the outside. I guess that's why they say not to judge a book by its cover.

Our last stop of the day was Colorado Springs. The 2005 remake of Assault on Precinct 13 was on HBO. I only saw the last 20 minutes of the movie but really enjoyed the action.

Days 5 and 6

The three of us went on the Patsy's Candies factory tour after breakfast. In my opinion, this tour was better than the one at Hammond's Candies. The samples were more plentiful and tasted better too. Hammond's Candies has a lot to learn from its competitors.

Our last stop in Colorado was the United States Air Force Academy campus. Security was tight as this was considered a military installation, but people here were very friendly and down-to-earth. The Cadet Chapel was closed for a private event but still made for some nice pictures.

It was then time to return to Denver International Airport for our flight home. One thing I wanted to do was visit Mrs. Tseng, one of my math teachers from LAHS who now lives in Aurora. However, this wasn't possible due to time constraints, not to mention we didn't even have her contact information on hand. Oh well, that's something to consider for a future trip.

We arrived home about 10 minutes after midnight due to unexpected flight delays. I guess that technically makes the trip six days long. All of us were completely exhausted and went to bed after unpacking.


On the whole, this was one of our most memorable vacations. I had no idea Colorado could be so beautiful. The best part of the trip was the Royal Gorge Bridge, although Estes Park comes a close second. The memories from this trip will last years. Feel free to look at the pictures.

At any rate, I should probably start preparing for my classes as the fall semester begins on the 26th. It has definitely been an awesome summer!

Currently listening to: The Sounds of the Rocky Mountains by Orange Tree Productions

Thursday, August 16, 2007

done with English N132

Today was the last English N132 lecture. Unlike the class I took last summer, this had a final exam. However, I don't think I did too badly on it as Prof. Loewinsohn was nice enough to give us a list of possible questions. If only more professors would do this. ^_^

In any case, I'm glad summer school is over. Speaking of which, the class also fulfilled my humanities requirement. W00t!

In other news...

1. I'm leaving for Colorado with my parents tomorrow afternoon. This will be our third trip of the year. To be honest, sometimes I think we travel too much...

2. I recently won another laser in a random drawing at a website called Spectra Forum. This one is more powerful than my 5 mW core and should arrive in the mail in a few days. I can't wait to add it to my collection. :-)

Currently reading: Light in August by William Faulkner